@classmethod
def load(cls, config_file):
    """ Load experiment parameters from a YAML configuration file

        Parameters
        ----------
        config_file: string
            path to a YAML configuration file

        Returns
        -------
        dictionary (or list of dictionaries) of parameters to pass to a behavior
        """
    try:
        import yaml
    except ImportError:
        raise ImportError(
            'Pyyaml is required to use a .yaml configuration file')
    parameters = list()
    with open(config_file, 'rb') as config:
        for val in yaml.load_all(config):
            parameters.append(val)
    if len(parameters) == 1:
        parameters = parameters[0]
    return parameters
