PY-18096 Fixed: False positive "Type doesn't have expected attributes" for namedtuple

Introduce PyClassLikeType.getMemberNames(boolean, TypeEvalContext). This method returns all members including dynamically ones (e.g. fields of namedtuple)

python/pluginJava/com/jetbrains/python/psi/impl/PyJavaClassType.java

@@ -31,9 +31,7 @@ import com.jetbrains.python.psi.types.TypeEvalContext;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 /**
  * @author yole
@@ -49,7 +47,7 @@ public class PyJavaClassType implements PyClassLikeType {
 
   @Nullable
   public List<? extends RatedResolveResult> resolveMember(@NotNull final String name,
-                                                          PyExpression location,
+                                                          @Nullable PyExpression location,
                                                           @NotNull AccessDirection direction,
                                                           @NotNull PyResolveContext resolveContext) {
     return resolveMember(name, location, direction, resolveContext, true);
@@ -156,6 +154,30 @@ public class PyJavaClassType implements PyClassLikeType {
     // TODO: Implement
   }
 
+  @NotNull
+  @Override
+  public Set<String> getMemberNames(boolean inherited, @NotNull TypeEvalContext context) {
+    final Set<String> result = new LinkedHashSet<>();
+
+    for (PsiMethod method : myClass.getAllMethods()) {
+      result.add(method.getName());
+    }
+
+    for (PsiField field : myClass.getAllFields()) {
+      result.add(field.getName());
+    }
+
+    if (inherited) {
+      for (PyClassLikeType type : getAncestorTypes(context)) {
+        if (type != null) {
+          result.addAll(type.getMemberNames(false, context));
+        }
+      }
+    }
+
+    return result;
+  }
+
   @NotNull
   @Override
   public List<PyClassLikeType> getAncestorTypes(@NotNull final TypeEvalContext context) {