'Convert ``value`` to the cache format; ``value`` may come from an
assignment, or have the format of methods :meth:`BaseModel.read` or
:meth:`BaseModel.write`. If the value represents a recordset, it should
be added for prefetching on ``record``.
:param bool validate: when True, field-specific validation of ``value``
will be performed'

def convert_to_cache(self, value, record, validate=True):

    return value
