Fix TypeError: _pretty() takes 1 positional argument but 2 were given…

… in sem/drt.py (#2854)

* Fix TypeError: _pretty() takes 1 positional argument but 2 were given in sem/drt.py

* Add as author.

Co-authored-by: Ahmet Yildirim <ahmet.yildirim@iln.uio.no>

AUTHORS.md

@@ -281,6 +281,7 @@
 - Ruben Cartuyvels <https://github.com/rubencart>
 - Dalton Pearson <https://github.com/daltonpearson>
 - Saibo Geng <https://github.com/Saibo-creator>
+- Ahmet Yildirim <https://github.com/RnDevelover>
 
 ## Others whose work we've taken and included in NLTK, but who didn't directly contribute it:
 

nltk/sem/drt.py

@@ -898,7 +898,7 @@ def _pretty(self):
         )
         if self.consequent:
             drs = DrtBinaryExpression._assemble_pretty(
-                drs, DrtTokens.IMP, self._pretty(self.consequent)
+                drs, DrtTokens.IMP, self.consequent._pretty()
             )
         return drs