<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _namespace_requested(self, namespace):
 """Checks whether the requested_namespaces contain the provided namespace"""

        if namespace is None:
            return False
        namespace_tuple = self._tuplefy_namespace(namespace)
        if namespace_tuple[0] in IGNORE_DBS:
            return False
        elif namespace_tuple[1] in IGNORE_COLLECTIONS:
            return False
        else:
            return self._tuple_requested(namespace_tuple)