code: def camel_case_to_under_score(camel_case_name):
      
      result = []
      for letter in camel_case_name:
          if letter.lower() != letter:
              result.append("_" + letter.lower())
          else:
              result.append(letter.lower())
      if result[0].startswith("_"):
          result[0] = result[0][1:]
      return "".join(result)
docs: Return the underscore name of a camel case name.
  
      :param str camel_case_name: a name in camel case such as
        ``"ACamelCaseName"``
      :return: the name using underscores, e.g. ``"a_camel_case_name"``
      :rtype: str