code: def find(self, title):
          
          if title not in self._titles:
              raise KeyError(title)
          return self._titles[title][0]
docs: Return the first worksheet with the given title.
  
          Args:
              title(str): title/name of the worksheet to return
          Returns:
              WorkSheet: contained worksheet object
          Raises:
              KeyError: if the spreadsheet has no no worksheet with the given ``title``