Wtihin dulwich.client, the get_ssh_vendor attribute is designed to be overridden by library callers:

A common example of this is for using Paramiko, where the ParamikoSSHVendor docs specifically instruct users to change this attribute:

However, there's no typing on get_ssh_vendor, which causes mypy to complain about the variable being assigned to another (thought-to-be-incompatible) type:

/my/module.py:92: error:
Incompatible types in assignment (expression has type
[ParamikoSSHVendor] "type", variable has type "type[SubprocessSSHVendor]")
[assignment]
            dulwich.client.get_ssh_vendor = ParamikoSSHVendor
                                            ^~~~~~~~~~~~~~~~~

Presumably, this should be typed to SSHVendor, given that anything assigned to that attribute needs to implement that class.