code: def camel_to_underscore(name):
      
      as_list = []
      length = len(name)
      for index, i in enumerate(name):
          if index != 0 and index != length - 1 and i.isupper():
              as_list.append('_%s' % i.lower())
          else:
              as_list.append(i.lower())
  
      return ''.join(as_list)
docs: convert CamelCase style to under_score_case