code: def capitalize(string):
      
      if not string:
          return string
      if len(string) == 1:
          return string.upper()
      return string[0].upper() + string[1:].lower()
docs: Capitalize a sentence.
  
      Parameters
      ----------
      string : `str`
          String to capitalize.
  
      Returns
      -------
      `str`
          Capitalized string.
  
      Examples
      --------
      >>> capitalize('worD WORD WoRd')
      'Word word word'