Use explicit "# type: str" instead of '' shortcut.

builtins/3/pwd.pyi

@@ -6,13 +6,13 @@ import typing
 
 class struct_passwd:
     # TODO use namedtuple
-    pw_name = ''
-    pw_passwd = ''
+    pw_name = ...  # type: str
+    pw_passwd = ...  # type: str
     pw_uid = 0
     pw_gid = 0
-    pw_gecos = ''
-    pw_dir = ''
-    pw_shell = ''
+    pw_gecos = ...  # type: str
+    pw_dir = ...  # type: str
+    pw_shell = ...  # type: str
 
 def getpwuid(uid: int) -> struct_passwd: ...
 def getpwnam(name: str) -> struct_passwd: ...