Locate all schemas (look in openldap store).

        If skip_missing_schemas is True, ignore missing schemas;
        otherwise, raise.

def _locate_schemas(self, schemas, skip_missing_schemas):
        """Locate all schemas (look in openldap store).

        If skip_missing_schemas is True, ignore missing schemas;
        otherwise, raise.
        """
        for schema in schemas:
            if schema == os.path.abspath(schema):
                schema_file = schema
            else:
                schema_file = os.path.join(self.paths.schemas, schema)

            if os.path.isfile(schema_file):
                # Absolute path: use it.
                yield schema_file
            elif skip_missing_schemas:
                logger.warning("Unable to locate schema %s at %s", schema, schema_file)
            else:
                raise PathError("Unable to locate schema %s at %s" % (schema, schema_file))