_constraints = [
(_bikecoop_activity_dates_check, 'Error: Bikecoop activity dates are inconsistent!', ['Bikecoop activity dates']),
(_rna_check, 'Error: RNA code must begin with a "W" followed by exactly 9 digits.', ['RNA']),
_constraints = [
(_bikecoop_activity_dates_check, 'Error: Bikecoop activity dates are inconsistent!', ['Bikecoop activity dates']),
(_rna_check, 'Error: RNA code must begin with a "W" followed by exactly 9 digits.', ['RNA']),