How to use the prophyle.prophyle_otu_table.Rank.CLASS function in prophyle

NO_RANK = 7
    SPECIES = 6
    GENUS = 5
    FAMILY = 4
    ORDER = 3
    CLASS = 2
    PHYLUM = 1
    KINGDOM = 0


str2rank = {
    'species': Rank.SPECIES,
    'genus': Rank.GENUS,
    'family': Rank.FAMILY,
    'order': Rank.ORDER,
    'class': Rank.CLASS,
    'phylum': Rank.PHYLUM,
    'kingdom': Rank.KINGDOM,
    'no rank': Rank.NO_RANK
}


def build_complete_tree(tree, log):
    """Build the taxonomic tree including internal nodes (for rank dependent evaluation)

    Args:
        tree (fileobject): file name of the reference tree, without internal nodes
        log (fileobject): log file
    """
    ncbi = NCBITaxa()
    original_tree = Tree(tree, format=1)
    taxa = [n.taxid for n in original_tree.traverse('postorder')]