code: def _rpad(self, length, pad=' '):
      
      return ops.RPad(self, length, pad).to_expr()
docs: Returns string of given length by truncating (on right)
      or padding (on right) original string
  
      Parameters
      ----------
      length : int
      pad : string, default is ' '
  
      Examples
      --------
      >>> import ibis
      >>> table = ibis.table([('string_col', 'string')])
      >>> expr = table.string_col.rpad(5, '-')
      >>> expr = ibis.literal('a').rpad(5, '-')  # 'a' becomes 'a----'
      >>> expr = ibis.literal('abcdefg').rpad(5, '-')  # 'abcdefg' becomes 'abcde'  # noqa: E501
  
      Returns
      -------
      padded : string