numpy iterable compatibility
@@ -174,7 +174,7 @@ class HolidayBase(dict):
self.expand = expand
if isinstance(years, int):
years = [years]
- self.years = set(years) if years else set()
+ self.years = set(years) if years is not None else set()
if not getattr(self, "prov", False):
self.prov = prov
self.state = state
