"""The HierRole class."""

from Role import Role

class HierRole(Role):
    """HierRole is a hierarchical role.

    It points to its parent roles. The hierarchy cannot have cycles.


    def __init__(self, name, description=None, superRoles=[]):
        Role.__init__(self, name, description)
        for role in superRoles:
            assert isinstance(role, Role)
        self._superRoles = superRoles[:]

    def playsRole(self, role):
        """Check whether the receiving role plays the role that is passed in.

        This implementation provides for the inheritance that HierRole supports.

        if self == role:
            return True
        for superRole in self._superRoles:
            if superRole.playsRole(role):
                return True
            return False