from sys import argvscript, input_file = argvdef print_all(f):    print f.read()    def rewind(f):    f.seek(0)def print_a_line(line_count, f):    print line_count, f.readline()current_file = open(input_file)print "First let‘s print the whole file:\n"print_all(current_file)print "Now let‘s rewind, kind of like a tape."rewind(current_file)print "Let‘s print three lines:"current_line = 1print_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)