old_contents: """CLC.PY: A SIMPLE PYTHON CALCULATOR."""
  import sys
  
  def add_all(nums):
      return sum(nums)
  
  def multiply_all(nums):
      return reduce(lambda a, b: a * b, nums)
  
  if __name__ == '__main__':
      command = sys.argv[1]
      nums = map(float, sys.argv[2:])
      if command == 'add':
          print(add_all(nums))
      elif command == 'multiply':
          print(multiply_all(nums))
  
new_contents: """CLC.PY: A SIMPLE PYTHON CALCULATOR."""
  import sys
  
  def add_all(nums):
      return sum(nums)
  
  def multiply_all(nums):
      return reduce(lambda a, b: a * b, nums)
  
  if __name__ == '__main__':
      command = sys.argv[1]
      nums = map(float, sys.argv[2:])
      if command == 'add':
          print(add_all(nums))
      elif command == 'multiply':
          print(multiply_all(nums))
  else:
          usage = "calc.py [add|multiply] NUM1 [NUM2 [NUM3 [...]]]"
          print(usage)
  
subject: Add usage string in calc