Recursively save arguments name and default value.

def fill_constants_types(module_name, elements):
    """ Recursively save arguments name and default value. """
    for elem, intrinsic in elements.items():
        if isinstance(intrinsic, dict):  # Submodule case
            fill_constants_types(module_name + (elem,), intrinsic)
        elif isinstance(intrinsic, ConstantIntr):
            # use introspection to get the Python constants types
            cst = getattr(__import__(".".join(module_name)), elem)
            intrinsic.signature = type(cst)