>>> from tours import find_art

>>> fest_dates_L = [
... [(2021,7,1), 'Vetusta Morla', 'Suu'],
... [(2021,7,2), 'Nathy Peluso', 'Stay Homas'],
... [(2021,7,3), 'Love of Lesbian', 'Clara Peya'] ]

>>> find_art('Suu', fest_dates_L)
(2021, 7, 1)
>>> find_art('Stay Homas', fest_dates_L)
(2021, 7, 2)
>>> find_art('Bet', fest_dates_L)
()