Create a NDArray function from the FunctionHandle.

def _make_ndarray_function(handle, name, func_name):
    """Create a NDArray function from the FunctionHandle."""
    code, doc_str = _generate_ndarray_function_code(handle, name, func_name)

    local = {}
    exec(code, None, local)  # pylint: disable=exec-used
    ndarray_function = local[func_name]
    ndarray_function.__name__ = func_name
    ndarray_function.__doc__ = doc_str
    ndarray_function.__module__ = 'mxnet.ndarray'
    return ndarray_function