def check_attr(attr):
    """
    Checks whether the attr is a class and whether
    it does inherit from Component and whether
    """
    from pybliotecario.components.component_core import Component
    if not isinstance(attr, type):
        return False
    if attr == Component:
        return False
    if issubclass(attr, Component):
        return (not Component.configure_me.__code__ == attr.configure_me.
            __code__)
    return False
