def load_rfam_urs_accessions_from_file(urs_acc_list):
    """
    Loads all existing Rfam URS accessions in a python
    dictionary

    urs_acc_list: A .txt file with all URS accession already
    in Rfam

    return: A python dictionary with all URS accessions as
    keys.
    """

    rfam_urs_accs = {}

    fp = open(urs_acc_list, 'r')

    for line in fp:
        accession = line.strip()
        if accession not in rfam_urs_accs:
            rfam_urs_accs[accession] = ""

    fp.close()

    return rfam_urs_accs