def read_classes_file(classes_filepath):
    """
    Read file that maps class names to class IDs. The file should be in the format:
        ActionName1 0
        ActionName2 1
    
    :param classes_filepath: str
        The filepath of the classes file
    :return: dict
        Mapping of class names to class IDs
    """
    classes = {}
    with open(classes_filepath) as class_file:
        for line in class_file:
            class_name, class_id = line.split(" ")
            classes[class_name] = class_id.rstrip()
    return classes