'List of resources that require this one as a dependency.
Returns a list of names of resources that depend on this resource
directly.'

def required_by(self):

    try:
        reqd_by = self.stack.dependencies.required_by(self)
    except KeyError:
        if self.stack.convergence:
            needed_by_ids = (self.needed_by or set())
            reqd_by = [r for r in self.stack.resources.values() if (r.id in needed_by_ids)]
        else:
            LOG.error('Getting    required_by    list    for    Resource    not    in    dependency    graph.')
            return []
    return [r.name for r in reqd_by]
