def find_col_by_key(info, key, value_prefix, value, default=None):
    """Given a list of dicts 'info', return the index for the first instance in
    which info[key] == value_prefix + value."""
    #print("find_col_by_key key: "+str(key)+", value: "+str(value_prefix+value));
    if info != None:
        for i in range(0, len(info)):
            if info[i].get(key) == value_prefix+value:
                return i
    return default