mypy: Account for Optional variables in addressee.py.
mypy: Account for Optional variables in addressee.py.

timabbott/zulip,andersk/zulip,hackerkid/zulip,shubhamdhama/zulip,punchagan/zulip,kou/zulip,showell/zulip,rht/zulip,punchagan/zulip,shubhamdhama/zulip,timabbott/zulip,eeshangarg/zulip,eeshangarg/zulip,synicalsyntax/zulip,andersk/zulip,synicalsyntax/zulip,synicalsyntax/zulip,zulip/zulip,hackerkid/zulip,rht/zulip,timabbott/zulip,jackrzhang/zulip,shubhamdhama/zulip,rht/zulip,rishig/zulip,shubhamdhama/zulip,zulip/zulip,showell/zulip,punchagan/zulip,rishig/zulip,punchagan/zulip,zulip/zulip,dhcrzf/zulip,hackerkid/zulip,synicalsyntax/zulip,dhcrzf/zulip,hackerkid/zulip,tommyip/zulip,rht/zulip,rishig/zulip,dhcrzf/zulip,dhcrzf/zulip,andersk/zulip,zulip/zulip,jackrzhang/zulip,tommyip/zulip,jackrzhang/zulip,synicalsyntax/zulip,showell/zulip,rht/zulip,hackerkid/zulip,brainwane/zulip,timabbott/zulip,jackrzhang/zulip,dhcrzf/zulip,zulip/zulip,jackrzhang/zulip,rishig/zulip,kou/zulip,rishig/zulip,andersk/zulip,synicalsyntax/zulip,kou/zulip,tommyip/zulip,andersk/zulip,punchagan/zulip,brainwane/zulip,shubhamdhama/zulip,jackrzhang/zulip,shubhamdhama/zulip,brainwane/zulip,tommyip/zulip,dhcrzf/zulip,rht/zulip,eeshangarg/zulip,kou/zulip,zulip/zulip,kou/zulip,rishig/zulip,timabbott/zulip,andersk/zulip,dhcrzf/zulip,brainwane/zulip,tommyip/zulip,timabbott/zulip,eeshangarg/zulip,kou/zulip,tommyip/zulip,synicalsyntax/zulip,eeshangarg/zulip,showell/zulip,rht/zulip,brainwane/zulip,eeshangarg/zulip,punchagan/zulip,zulip/zulip,showell/zulip,showell/zulip,punchagan/zulip,kou/zulip,eeshangarg/zulip,brainwane/zulip,showell/zulip,shubhamdhama/zulip,hackerkid/zulip,timabbott/zulip,rishig/zulip,andersk/zulip,hackerkid/zulip,brainwane/zulip,jackrzhang/zulip,tommyip/zulip