code: def increment_cell_value(self, column_family_id, column, int_value):
          
          column = _to_bytes(column)
          rule_pb = data_v2_pb2.ReadModifyWriteRule(
              family_name=column_family_id,
              column_qualifier=column,
              increment_amount=int_value,
          )
          self._rule_pb_list.append(rule_pb)
docs: Increments a value in an existing cell.
  
          Assumes the value in the cell is stored as a 64 bit integer
          serialized to bytes.
  
          .. note::
  
              This method adds a read-modify rule protobuf to the accumulated
              read-modify rules on this row, but does not make an API
              request. To actually send an API request (with the rules) to the
              Google Cloud Bigtable API, call :meth:`commit`.
  
          For example:
  
          .. literalinclude:: snippets_table.py
              :start-after: [START bigtable_row_increment_cell_value]
              :end-before: [END bigtable_row_increment_cell_value]
  
          :type column_family_id: str
          :param column_family_id: The column family that contains the column.
                                   Must be of the form
                                   ``[_a-zA-Z0-9][-_.a-zA-Z0-9]*``.
  
          :type column: bytes
          :param column: The column within the column family where the cell
                         is located.
  
          :type int_value: int
          :param int_value: The value to increment the existing value in the cell
                            by. If the targeted cell is unset, it will be treated
                            as containing a zero. Otherwise, the targeted cell
                            must contain an 8-byte value (interpreted as a 64-bit
                            big-endian signed integer), or the entire request
                            will fail.