icalendar<7.0.0,>=5.0.0
python-dateutil<3.0.0,>=2.8.1

[:python_version <= "3.8"]
x-wr-timezone==0.*

[:python_version == "3.7" or python_version == "3.8"]
backports.zoneinfo

[:python_version >= "3.7"]
tzdata

[:python_version >= "3.9"]
x-wr-timezone==1.*