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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pause( msg = None ):
 """ Prints the line number and waits for a keypress. If you press: This is useful for debugging. """

    f = sys._getframe(1)
    ff = f.f_code
    if (msg):
        print '%s, %d: %s(), %d: %s' % (ff.co_filename, ff.co_firstlineno,
                                        ff.co_name, f.f_lineno, msg)
    else:
        print '%s, %d: %s(), %d' % (ff.co_filename, ff.co_firstlineno,
                                    ff.co_name, f.f_lineno)
    spause()