curryable functions in python - no kwargs yet

curry.py

import inspect
from functools import partial

def curryable(func):
    spec = inspect.getargspec(func)
    nargs = len(spec.args)
    if spec.varargs:
        raise ValueError('Hard to make a multiarity function curryable')
    if spec.defaults:
        raise ValueError('Hard to make a function with default arguments curryable')
        #TODO try to keep kwargs working
    def curryable_function(local_func, args_left):
        def new_func(*args):
            if len(args) > args_left:
                raise TypeError('func takes %d args at in this form, %d args total' % (args_left, nargs))
            elif len(args) == args_left:
                return local_func(*args)
            else:
                return curryable_function(partial(local_func, *args), args_left - len(args))
        return new_func

    return curryable_function(func, nargs)

@curryable
def foo(x, y, z):
    return x + y + z

print foo(1,2,3)
print foo(1)(2)(3)
print foo(1, 2)(3)
print foo(1)(2, 3)

Should write this in Python 3.3 so signatures can be dynamically set