load arbitrary functions - note, on the fs test1 and test2 should be in the lib directory

loader.py

import os, os.path
import lib
import types

def init():
    #walk lib and import modules
    module_set = set([os.path.splitext(module)[0] for module in os.listdir('lib') if not module.startswith('__init__')])
    module_set = [m for m in module_set]
    mods = __import__('lib',globals(), locals(), module_set, -1)
    return mods, module_set

def grab_func(f_name, mods, module_set):
    for m in module_set:
        
        mod = getattr(mods, m)
        print [mod.__dict__.get(a) for a in dir(mod) if isinstance(mod.__dict__.get(a),types.FunctionType)]

            
def load_and_call(f_name):
    mods, mod_set = init()
    grab_func(f_name, mods, mod_set)


if __name__ == "__main__":
    load_and_call('test1_f2')

test1.py

def test1_f1(*args, **kwargs):
    print 'test_f1'

def test1_f2(*args,**kwargs):
    print 'test_f2'

test2.py

def test2_f1(*args, **kwargs):
    print 'test_f1'

def test2_f2(*args,**kwargs):
    print 'test_f2'