For core OTU data file, returns Genus-species identifier for each data
    entry.
    :type core_fp: str
    :param core_fp: A file containing core OTU data.
    :rtype: str
    :return: Returns genus-species identifier based on identified taxonomical
             level.

def load_core_file(core_fp):
    """
    For core OTU data file, returns Genus-species identifier for each data
    entry.
    :type core_fp: str
    :param core_fp: A file containing core OTU data.
    :rtype: str
    :return: Returns genus-species identifier based on identified taxonomical
             level.
    """
    with open(core_fp, "rU") as in_f:
        return {otu_name(ast.literal_eval(line.split("\t")[1]))
                for line in in_f.readlines()[1:]}