def _parse_depot_section(f):
    """Parse TSPLIB DEPOT_SECTION data part from file descriptor f
    
    Args
    ----
    f : str
        File descriptor
    Returns
    -------
    int
        an array of depots
    """
    depots = []

    for line in f:
        line = strip(line)
        if line == '-1' or line == 'EOF': # End of section
            break
        else:
            depots.append(line)

    if len(depots) != 1:
        raise ParseException('One and only one depot is supported')

    return int(depots[0])