def get_function(module_name, function_name):
    """Gets the callable function with name function_name

    Args:
        module_name: The module where our function is defined
        function_name: The name of the function we'd like to load
            programatically

    Returns:
        The callable function.
    """
    func_path = module_name.split('.') + function_name.split('.')
    reference = __import__(module_name)
    for name in func_path[1:]:
        reference = getattr(reference, name)
    return reference
