def siteid_to_filename(sites, file_label, ext='csv'):
    """
    Given a list of site ids returns a list of strings corresponding to the file name obtained by concatenating it to
    the 'file_label` string.  For `sites` in ['1', '2'] with `file_label`='_signal', this method will return the list
    ['1_signal.csv', '2_signal.csv'].
    :param sites: List of strings containing the file id, i.e. non-repeating part of the input signal csv file names.
    :param file_label: String. Repeating part of the input signal csv file name.
    :param ext: String, optional. Input signal file extension
    :return: full file name corresponding to site ids in `sites` list
    """
    checked_sites = []
    for site_id in sites:
        file_name = site_id + file_label + ext
        checked_sites.append(file_name)
    return checked_sites