code: def _sincedb_start_position(self):
          
          if not self._sincedb_path:
              return None
  
          self._sincedb_init()
          self._log_debug('retrieving start_position from sincedb')
          conn = sqlite3.connect(self._sincedb_path, isolation_level=None)
          cursor = conn.cursor()
          cursor.execute('select position from sincedb where fid = :fid and filename = :filename', {
              'fid': self._fid,
              'filename': self._filename
          })
  
          start_position = None
          for row in cursor.fetchall():
              start_position, = row
  
          return start_position
docs: Retrieves the starting position from the sincedb sql db
          for a given file