Convenience method to update this Di instance with the specified contents.

        :param catalog: ICatalog supporting class or mapping
        :type catalog: ICatalog or collections.Mapping
        :param dependencies: Mapping of dependencies
        :type dependencies: collections.Mapping
        :param allow_overwrite: If True, allow overwriting existing keys. Only applies to providers.
        :type allow_overwrite: bool

def update(self, catalog=None, dependencies=None, allow_overwrite=False):
        '''
        Convenience method to update this Di instance with the specified contents.

        :param catalog: ICatalog supporting class or mapping
        :type catalog: ICatalog or collections.Mapping
        :param dependencies: Mapping of dependencies
        :type dependencies: collections.Mapping
        :param allow_overwrite: If True, allow overwriting existing keys. Only applies to providers.
        :type allow_overwrite: bool
        '''
        if catalog:
            self._providers.update(catalog, allow_overwrite=allow_overwrite)
        if dependencies:
            self._dependencies.update(dependencies)