class CircDep(Exception):
    """CircDep is raised when dependency resolver encounters circular dependency.
    The only useful member 'path' gives full dependency circle."""
    path = []
    def __init__(self, a):
        self.path = a

def ResolveDeps(deps):
    """ Dependency resolver. The only argument points to a dictionary,
    keys of which point to nodes to be resolved and appropriate values point
    to lists of dependency nodes. """
    def resnode(node, resolved, path):
        """ Auxiliary function, that goes into tree of deps, finds its
        leaves or resolved subtrees and adds them to 'resolved'. """
        if node in path:
            raise CircDep(path + [node])
        if node not in deps:
            resolved.append(node)
            return None
        for item in deps[node]:
            if item in resolved: continue
            resnode(item, resolved, path + [node])
        resolved.append(node)
        return None
    res = []
    for node in deps.keys():
        if node not in res: resnode(node, res, [])
    return res