code: def underscore(name):
      '''
      Transform CamelCase -> snake_case.
      '''
  
      s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
      return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower(f underscore(name):
      '''
      Transform CamelCase -> snake_case.
      '''
  
      s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
      return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
docs: Transform CamelCase -> snake_case.