def _block_size(sep):
    """
    Determine the size of a FITS header block if a non-blank separator is used
    between cards.
    """

    return BLOCK_SIZE + (len(sep) * (BLOCK_SIZE // Card.length - 1))
dataset/ETHPy150Open spacetelescope/PyFITS/pyfits/header.py/_block_size/original