method to find the start and end parameter markers
    on a template file line.  Used by write_to_template()

    Parameters
    ----------
    marker : str
        template file marker char
    line : str
        template file line

    Returns
    -------
    indices : list
        list of start and end indices (zero based)

def get_marker_indices(marker,line):
    """ method to find the start and end parameter markers
    on a template file line.  Used by write_to_template()

    Parameters
    ----------
    marker : str
        template file marker char
    line : str
        template file line

    Returns
    -------
    indices : list
        list of start and end indices (zero based)

    """
    indices = [i for i, ltr in enumerate(line) if ltr == marker]
    start = indices[0:-1:2]
    end = [i+1 for i in indices[1::2]]
    assert len(start) == len(end)
    return start,end