Better format complex conditional

Author: fperrin

mypy/messages.py

@@ -1975,12 +1975,12 @@ def [T <: int] f(self, x: int, y: T) -> None
             s += ' = ...'
 
     # If we got a "special arg" (i.e: self, cls, etc...), prepend it to the arg list
-    if isinstance(tp.definition, FuncDef) and \
-       tp.definition.name is not None and \
-       tp.definition.arguments:
+    if (isinstance(tp.definition, FuncDef) and
+            tp.definition.name is not None and
+            tp.definition.arguments):
         definition_args = [arg.variable.name for arg in tp.definition.arguments]
-        if definition_args and tp.arg_names != definition_args \
-           and len(definition_args) > 0 and definition_args[0]:
+        if (tp.arg_names != definition_args and
+                definition_args[0]):
             if s:
                 s = ', ' + s
             s = definition_args[0] + s