'Get a destination parameter that can be defaulted back
in specified config if it needs to be applied globally.'

def get_destination_configuration(self, config, key, default=None):

    param_unspecified = object()
    config_value = (self.destination_params or {}).get(key, param_unspecified)
    if (config_value is param_unspecified):
        config_value = getattr(config, key, param_unspecified)
    if (config_value is param_unspecified):
        config_value = default
    return config_value
