selfloading.py

import os

from traitlets import Unicode
from traitlets.config import Configurable, PyFileConfigLoader

class MyClass(Configurable):
    thing = Unicode('default').tag(config=True)
    
    # you can pick a default config file location:
    _default_config_file = os.path.expanduser('~/.myconfig.py')
    
    def load_config_file(self, config_file=None):
        """Load a config file. Load default config file if unspecified."""
        if config_file is None:
            config_file = self._default_config_file
        loader = PyFileConfigLoader(config_file)
        config = loader.load_config()
        # trigger config-loading
        self.update_config(config)


c = MyClass()
print('before: thing=%s' % c.thing)
c.load_config_file('test_config.py')
# test_config.py has just : c.MyClass.thing = 'from file'
print('after: thing=%s' % c.thing)