def getParamNames(v):
    """
    Takes a VOEvent and produces a list of pairs of group name and param name.
    For a bare param, the group name is the empty string.
    """
    list = []
    w = v.get_What()
    if not w:
        return list
    for p in v.get_What().get_Param():
        list.append(('', p.get_name()))
    for g in v.get_What().get_Group():
        for p in v.get_What().get_Param():
            list.append((g.get_name(), p.get_name()))
    return list
