def chute_find_field(chute, key, default=Exception):
    """
    Find a field in a chute definition loading from a paradrop.yaml file.
    """
    if key in chute:
        return chute[key]
    elif 'config' in chute and key in chute['config']:
        return chute['config'][key]
    elif isinstance(default, type):
        raise default('{} field not found in chute definition.'.format(key))
    else:
        return default
