code: def genfirstvalues(cursor: Cursor, arraysize: int = 1000) \
          -> Generator[Any, None, None]:
      
      return (row[0] for row in genrows(cursor, arraysize))
docs: Generate the first value in each row.
  
      Args:
          cursor: the cursor
          arraysize: split fetches into chunks of this many records
  
      Yields:
          the first value of each row