code: def get_worksheet(self, index):
          
          sheet_data = self.fetch_sheet_metadata()
  
          try:
              properties = sheet_data['sheets'][index]['properties']
              return Worksheet(self, properties)
          except (KeyError, IndexError):
              return None
docs: Returns a worksheet with specified `index`.
  
          :param index: An index of a worksheet. Indexes start from zero.
          :type index: int
  
          :returns: an instance of :class:`gsperad.models.Worksheet`
                    or `None` if the worksheet is not found.
  
          Example. To get first worksheet of a spreadsheet:
  
          >>> sht = client.open('My fancy spreadsheet')
          >>> worksheet = sht.get_worksheet(0)