<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_namespace( self, namespace: str, lowercase: bool=True, trim_namespace: bool=True, ) -> Dict[str, Any]: """Return a dictionary of keys within a namespace. A namespace is considered to be a key prefix, for example the keys ``FOO_A, FOO_BAR, FOO_B`` are all within the ``FOO`` namespace. This method would return a dictionary with these keys and values present. .. code-block:: python config = {'FOO_A': 'a', 'FOO_BAR': 'bar', 'BAR': False} app.config.from_mapping(config) assert app.config.get_namespace('FOO_') == {'a': 'a', 'bar': 'bar'} Arguments: namespace: The namespace itself (should be uppercase). lowercase: Lowercase the keys in the returned dictionary. trim_namespace: Remove the namespace from the returned keys. """

        config = {}
        for key, value in self.items():
            if key.startswith(namespace):
                if trim_namespace:
                    new_key = key[len(namespace):]
                else:
                    new_key = key
                if lowercase:
                    new_key = new_key.lower()
                config[new_key] = value
        return config