Update app.py

app.py

@@ -105,7 +105,7 @@ def update(sequence=DEFAULT_SEQ):
     name = sequence[:3] + sequence[-3:] 
     pdb_filename = "test.pdb"
     pdb_string = response.content.decode('utf-8')
-    with tempfile.TemporaryFile(mode = "w") as tmp:
+    with tempfile.TemporaryFile(mode = "rw") as tmp:
         tmp.write(pdb_string)
 
     return molecule(tmp.name), tmp.name