Coerce URL to string when using mf2py parser

             self.ok = self.response.ok
             self.text = self.response.text
             self.headers = self.response.headers
-        self.url = str(self.url)
 
     def __repr__(self):
         return f"<web.agent.Transaction object for {self.url}>"

     @property
     def mf2json(self):
         # return Semantics(mf.parse(Document(self.text, self.url).html, self.url))
-        return mf.parse(url=self.url)
+        return mf.parse(url=str(self.url))
 
     @property
     def card(self):