[Discuss-gnuradio] Where is the modulation in Modulation_utils

Hi all,

   I am really confused. I opened the modulation_utils and I cannot figure out how the modulation part is performed, it is just an empty curly braces.

_type_1_modulators = {}

def type_1_mods():
    return _type_1_modulators

def add_type_1_mod(name, mod_class):
    _type_1_modulators[name] = mod_class

Would anybody resolves this for me.

Thanks