def _serialize(self, value, attr, obj, **kwargs):
        """Return a string if `self.as_string=True`, otherwise return this field's `num_type`."""
        ret = self._validated(value)
        return (
            self._to_string(ret)
            if (self.as_string and ret not in (None, missing_))
            else ret
        )
def _serialize ( self , value , attr , obj , ** kwargs ) : ret = self . _validated ( value ) return ( self . _to_string ( ret ) if ( self . as_string and ret not in ( None , missing_ ) ) else ret )
Return a string if `self.as_string=True`, otherwise return this field's `num_type`.