human
Complete this python program:
def jitclass(spec):
assistant
#Here is the Python program you requested.

    """A decorator for creating a jitclass.
    **arguments**:
    - spec:
    Specifies the types of each field on this class.
    Must be a dictionary or a sequence.
    With a dictionary, use collections.OrderedDict for stable ordering.
    With a sequence, it must contain 2-tuples of (fieldname, fieldtype).
    **returns**:
    A callable that takes a class object, which will be compiled.
    """
    def wrap(cls):
        if config.DISABLE_JIT:
            return cls
        else:
            return register_class_type(cls, spec, types.ClassType, ClassBuilder)
    return wrap