_pickle.UnpicklingError: invalid load key, '\x0a'

hi there
I am trying to load a .pb model through this functions below and I get this error
“_pickle.UnpicklingError: invalid load key, ‘\x0a’.”
any help please

def load_network_pkl(run_id_or_result_subdir_or_network_pkl, snapshot=None):
    return load_pkl(locate_network_pkl(run_id_or_result_subdir_or_network_pkl, snapshot))

def load_pkl(filename):
    with open(filename, 'rb') as file:
        return legacy.LegacyUnpickler(file, encoding='latin1').load()

> #the load() function is from pickle package 

class LegacyUnpickler(pickle.Unpickler):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)