def validate_email(self, attribute, value):
"""Check that provided email addresses are valid."""
if not all(map(lambda e: is_email(e), value)):
raise ValueError(f"Invalid email in DAG email: {value}.")
def validate_owner(self, attribute, value):
"""Check that owner is a valid email address."""
if not is_email(value):
raise ValueError(f"Invalid email for task owner: {value}.")
