Finds the L{ClassAlias} that is registered to C{klass_or_alias}.

    If a string is supplied and no related L{ClassAlias} is found, the alias is
    loaded via L{load_class}.

    @raise UnknownClassAlias: Unknown alias

def get_class_alias(klass_or_alias):
    """
    Finds the L{ClassAlias} that is registered to C{klass_or_alias}.

    If a string is supplied and no related L{ClassAlias} is found, the alias is
    loaded via L{load_class}.

    @raise UnknownClassAlias: Unknown alias
    """
    if isinstance(klass_or_alias, python.str_types):
        try:
            return CLASS_CACHE[klass_or_alias]
        except KeyError:
            return load_class(klass_or_alias)

    try:
        return CLASS_CACHE[klass_or_alias]
    except KeyError:
        raise UnknownClassAlias('Unknown alias for %r' % (klass_or_alias,))