def ingest(in_info):
    """
    Function reading in parameter file to define functions necessary for
    generation of posterior probability distributions

    Parameters
    ----------
    in_info: string or dict
        string containing path to plaintext input file or dict containing
        likelihood input parameters

    Returns
    -------
    in_dict: dict
        dict containing keys and values necessary for posterior probability
        distributions
    """
    if type(in_info) == str:
        with open(in_info) as infile:
            lines = (line.split(None) for line in infile)
            in_dict = {defn[0] : defn[1:] for defn in lines}
    else:
        in_dict = in_info
    return in_dict