Python: Convert an xml/html document as defined by dict/list/string into an xpath string?

I want to define an xml element as a dictionary or string or list or whatever. This will be just a description of an xml element. It doesn't need to exist (that's why I don't use lxml or other libraries). For example having this

my_xml = {
            "tag"       : "input",
            "attribute" : ("value", "Login")
         },

I want to get this

input[@value="Login"]

Does a module exist that can do that? I started doing my own implementation but want to be sure that I am not reinventing the wheel. Cheers!