(meta, *bases)
return metaclass("NewBase", None, {})
Create a base class with a metaclass.

    For example, if you have the metaclass

    >>> class Meta(type):
    ...     pass

    Use this as the metaclass by doing

    >>> from sympy.core.compatibility import with_metaclass
    >>> class MyClass(with_metaclass(Meta, object)):
    ...     pass

    This is equivalent to the Python 2::

        class MyClass(object):
            __metaclass__ = Meta

    or Python 3::

        class MyClass(object, metaclass=Meta):
            pass

    That is, the first argument is the metaclass, and the remaining arguments
    are the base classes. Note that if the base class is just ``object``, you
    may omit it.

    >>> MyClass.__mro__
    (<class 'MyClass'>, <... 'object'>)
    >>> type(MyClass)
    <class 'Meta'>
Create a base class with a metaclass.
Create a base class with a metaclass .
def with_metaclass(meta, *bases):
    """
    Create a base class with a metaclass.

    For example, if you have the metaclass

    >>> class Meta(type):
    ...     pass

    Use this as the metaclass by doing

    >>> from sympy.core.compatibility import with_metaclass
    >>> class MyClass(with_metaclass(Meta, object)):
    ...     pass

    This is equivalent to the Python 2::

        class MyClass(object):
            __metaclass__ = Meta

    or Python 3::

        class MyClass(object, metaclass=Meta):
            pass

    That is, the first argument is the metaclass, and the remaining arguments
    are the base classes. Note that if the base class is just ``object``, you
    may omit it.

    >>> MyClass.__mro__
    (<class 'MyClass'>, <... 'object'>)
    >>> type(MyClass)
    <class 'Meta'>

    """
    class metaclass(meta):
        __call__ = type.__call__
        __init__ = type.__init__
        def __new__(cls, name, this_bases, d):
            if this_bases is None:
                return type.__new__(cls, name, (), d)
            return meta(name, bases, d)
    return metaclass("NewBase", None, {})
def with_metaclass ( meta , * bases ) : class metaclass ( meta ) : __call__ = type . __call__ __init__ = type . __init__ def __new__ ( cls , name , this_bases , d ) : if this_bases is None : return type . __new__ ( cls , name , ( ) , d ) return meta ( name , bases , d ) return metaclass ( "NewBase" , None , { } )