Returns the capitalized relation name from a tree's satellite
    subtree label, e.g. 'satellite:contrast' becomes 'Contrast'.

def get_capitalized_relname(tree, subtree_index):
    """Returns the capitalized relation name from a tree's satellite
    subtree label, e.g. 'satellite:contrast' becomes 'Contrast'.
    """
    match = HS2015_REL_RE.match(tree[subtree_index].label())
    relname = match.group('relname')
    return relname.capitalize()