def _validate_member(self, member, classes, instanceof):
log.info("<STR_LIT>" % member)<EOL>stripped = self._get_stripped_attributes(member, classes)<EOL>if self._field_name_from_uri(member) in stripped:<EOL><INDENT>all_class_members = sum([self.schema_def.attributes_by_class[cl]<EOL>for cl in classes], [])<EOL>if member in all_class_members:<EOL><INDENT>return<EOL><DEDENT>if self._namespace_from_uri(member) in self.allowed_namespaces:<EOL><INDENT>err = self.err("<STR_LIT>",<EOL>self._namespace_from_uri(member))<EOL>return ValidationWarning(ValidationResult.WARNING, err['<STR_LIT>'],<EOL>err['<STR_LIT>'], err['<STR_LIT>'])<EOL><DEDENT><DEDENT>else:<EOL><INDENT>err = self.err("<STR_LIT>",<EOL>self._field_name_from_uri(member),<EOL>self._field_name_from_uri(instanceof))<EOL>return ValidationWarning(ValidationResult.ERROR, err['<STR_LIT>'],<EOL>err['<STR_LIT>'], err['<STR_LIT>'])<EOL><DEDENT>
return error if `member` is not a member of any class in
        `classes`