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# Call above function here.temp_convert("xyz");This would produce the following result:The argument does not contain numbersinvalid literal for int() with base 10: 'xyz'Raising an exceptions: You can raise exceptions in several ways by using the raise statement. The general syntax for the raisestatement.SYNTAX: raise [Exception [, args [, traceback]]]Here, Exception is the type of exception (for example, NameError) and argument is a value for the exceptionargument. The argument is optional; if not supplied, the exception argument is None.The final argument, traceback, is also optional (and rarely used in practice), and if present, is the traceback objectused for the exception.EXAMPLE: An exception can be a string, a class or an object. Most of the exceptions that the Python core raises are classes,with an argument that is an instance of the class. Defining new exceptions is quite easy and can be done asfollows:def functionName( level ):if level < 1:raise "Invalid level!", level# The code below to this would not be executed# if we raise the exceptionNote: In order to catch an exception, an "except" clause must refer to the same exception thrown either classobject or simple string. For example, to capture above exception, we must write our except clause as follows:try:Business Logic here...except "Invalid level!":Exception handling here...else:Rest of the code here...User-‐Defined Exceptions: Python also allows you to create your own exceptions by deriving classes from the standard built-in exceptions.Here is an example related to RuntimeError. Here, a class is created that is subclassed from RuntimeError. Thisis useful when you need to display more specific information when an exception is caught.In the try block, the user-defined exception is raised and caught in the except block. The variable e is used tocreate an instance of the class Networkerror.class Networkerror(RuntimeError):def __init__(self, arg):TUTORIALS POINT Simply Easy Learning
self.args = argSo once you defined above class, you can raise your exception as follows:try:raise Networkerror("Bad hostname")except Networkerror,e:print e.argsTUTORIALS POINT Simply Easy Learning
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Python Tutorial
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ABOUT THE TUTORIALPython TutorialPy
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Return Value ......................
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Description .......................
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Syntax ............................
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Example ...........................
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Parameters ........................
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Return Value ......................
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Parameters ........................
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Parameters ........................
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Locating Modules: .................
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Parameters ........................
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Description .......................
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Return Value ......................
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Example ...........................
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Parameters ........................
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Regular-expression Modifiers - Opti
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Starting a New Thread: ............
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Example: ..........................
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CHAPTER1Python OverviewPython is a
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CHAPTER2Python EnvironmentBefore we
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• To use this installer python-XY
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-c cmd run Python script sent in as
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This will produce the following res
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file_name = raw_input("Enter filena
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$ python -husage: python [option] .
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print 'Input file is "', inputfilep
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Here, an integer object is created
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Python Lists: Lists are the most v
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FunctionDescriptionint(x [,base])Co
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CHAPTER5Python Basic OperatorsWhat
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Line 4 - Value of c is 2Line 5 - Va
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Line 5 - a is greater than bLine 6
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| Binary OR Operator copies a bit i
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else:print "Line 3 - a and b are tr
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if ( id(a) == id(b) ):print "Line 2
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When you execute the above program,
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if statementsif...else statementsne
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Example: #!/usr/bin/pythonvar1 = 10
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else:print "Could not find true exp
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Loop Typewhile loopfor loopDescript
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num = raw_input("Enter a number :")
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Good bye!Iterating by Sequence I
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11 is prime13 is prime17 is prime19
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continue statement The continue st
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CHAPTER8Python NumbersNumber data t
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max(x1, x2,...)min(x1, x2,...)modf(
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Syntax Following is the syntax for
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import math# This will import math
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import mathmath.log10( x )Note: Thi
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modf(x) Description The method modf
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round( x [, n] )Parameters • x --
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Return Value This method returns a
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seed([x]) Description The method se
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asin(x)Note: This function is not a
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print "atan2(-10,10) : ", math.atan
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Note: This function is not accessib
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import mathprint "degrees(3) : ", m
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CHAPTER9Python StringsStrings are a
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+ Concatenation - Adds values on ei
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TAB ( \t ) and they will show up th
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str = "this is string example....wo
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Return Value This method returns a
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Description The method expandtabs()
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Traceback (most recent call last):F
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Let us compile and run the above pr
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str = "This is string example....wo
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str = "-";seq = ("a", "b", "c"); #
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lstrip() Description The method lst
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Max character: xmin(str) Descriptio
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str = "this is really a string exam
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Parameters • chars -- You can sup
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Parameters• str -- This is the st
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Parameters • NAReturn Value This
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Example The following example shows
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CHAPTER10Python ListsThe most basic
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Python Expression Results Descripti
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list( seq )Parameters • seq -- Th
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Return Value If elements are of th
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list.insert(index, obj)Parameters
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CHAPTER11Python TuplesAtuple is a s
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len((1, 2, 3)) 3 Length(1, 2, 3) +
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-11-1len(tuple) Description The met
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min value element : 200tuple(seq) D
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#!/usr/bin/pythondict = {'Name': 'Z
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34str(dict)Produces a printable str
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type(variable) Description The meth
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Return Value This method does not
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CHAPTER13Python Date & TimeApython
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#!/usr/bin/pythonimport time;localt
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import timeprint "time.altzone %d "
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Parameters • sec -- These are the
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• %w - day of the week as a decim
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time.time( ) Description The metho
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2time.tznameAttribute time.tzname i
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CHAPTER14Python FunctionAfunction i
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#!/usr/bin/python# Function definit
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return;# Now you can call printinfo
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Inside the function : 30Outside the
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A module is loaded only once, regar
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'sqrt', 'tan', 'tanh']Here, the spe
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CHAPTER16Python Files I/OThis chapt
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rb+WWbw+wb+AAba+ab+Opens a file for
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fo.write( "Python is a great langua
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EXAMPLE: Following is the example t
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operations from the operating syste
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# Close opened filefo.close()Let us
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Parameters • NAReturn Value This
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Parameters • offset -- This is th
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Parameters • size -- If this opti
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Description The method writelines()
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53545556575859606162os.symlink(src,
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Return Value This method does not
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• stat.S_IRGRP: Read by group.•
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os.chroot("/tmp/usr")print "Changed
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Parameters • fd -- This is the or
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import os, sys# First go to the "/v
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Description The method fchown() cha
Page 257 and 258: Description The method fdopen() ret
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Page 261 and 262: Example The following example shows
Page 263 and 264: # Open a filefd = os.open( "foo.txt
Page 265 and 266: print "Current working dir : %s" %
Page 267 and 268: path = "/var/www/html/foo.txt"fd =
Page 269 and 270: Example The following example shows
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Page 273 and 274: # Close opened fileos.close( fd )#
Page 275 and 276: dev_num = os.makedev(major_dnum, mi
Page 277 and 278: Return Value This method does not
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Page 281 and 282: os.pathconf(path, name) Descriptio
Page 283 and 284: Description The method popen() open
Page 285 and 286: # !/usr/bin/pythonimport ossrc = '/
Page 287 and 288: Syntax Following is the syntax for
Page 291 and 292: # stat informationstatinfo = os.sta
Page 293 and 294: Description The method tcgetpgrp()
Page 295 and 296: os.tempnam(dir, prefix)Parameters
Page 297 and 298: Description The method ttyname() re
Page 301 and 302: Return Value This method returns t
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Page 307: print "Error: can\'t find file or r
Page 311 and 312: 'Optional class documentation strin
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Page 315 and 316: print 'Calling child method'c = Chi
Page 317 and 318: Data Hiding: An object's attribute
Page 319 and 320: groups()This method returns all mat
Page 321 and 322: SYNTAX: re.sub(pattern, repl, strin
Page 323 and 324: \s Matches whitespace. Equivalent t
Page 325 and 326: Backreferences: This matches a prev
Page 327 and 328: CHAPTER20Python CGI ProgrammingWhat
Page 329 and 330: If you click hello.py, then this pr
Page 331 and 332: Simple URL Example : Get Metho
Page 333 and 334: </form>The result of this code is t
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Page 337 and 338: Here is an example of how to retrie
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Page 345 and 346: DELETE Operation: DELETE operation
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Page 349 and 350: The socket Module: To create a so
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Page 353 and 354: Subject: SMTP e-mail testThis is a
Page 355 and 356: try:smtpObj = smtplib.SMTP('localho
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Synchronizing Threads: The threadi
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thread = myThread(threadID, tName,
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<stars>10</stars><description>Talk
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print "Rating:", self.ratingelif se
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Format: DVDRating: PGDescription: T
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Tkinter Widgets Tkinter provides v
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fgfontheighthighlightcolorimagejust
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WidthXscrollincrementXscrollcommand
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pattern when it is over the checkbu
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The Entry widget is used to accept
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E1 = Entry(top, bd =5)E1.pack(side
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Optionanchorbgbitmapbdcursorfontfgh
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selectmodeDetermines how many items
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Syntax: Here is the simple syntax t
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Menu The goal of this widget is to
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filemenu.add_command(label="Exit",
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Example: Try the following example
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WidthWraplengthWidth of the label i
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label appears in the top left corne
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Parameters: • master: This repres
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Parameters: • master: This repres
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mark_gravity(mark [,gravity])Return
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Methods & Descriptiondeiconify()Dis
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disabledbackgrounddisabledforegroun
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bgbdThe color of the slider and arr
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fontheightlabelAnchorhighlightbackg
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Standard attributes:Let's take a l
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• family: The font family name as
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B2.pack()B3.pack()B4.pack()B5.pack(
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• "heart"• "heart"• "man"•
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The grid() Method This geometry m
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CHAPTERPython Further Extensions27A
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This table needs to be terminated w
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Passing Function Parameters: Beca
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return (a + b)You can return two va
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CHAPTER28Python Tools/UtilitiesThe
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The profile Module: The profile m
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