Test Errors/Failures with Python 3.7 & VTK 7

I'm seeing a few errors & failures when running the unit tests under Python 3.7 and VTK 7, see below. I don't see this particular combination in the Travis configuration, so perhaps it has not been tested?

Python: 3.7.6
vtk: 7.1.1
mayavi: 4.7.1

```
======================================================================
ERROR: test_decorated_scene (test_garbage_collection.TestTVTKGarbageCollection)
Tests if Decorated Scene can be garbage collected.
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_garbage_collection.py", line 50, in test_decorated_scene
self.check_object_garbage_collected(create_fn, close_fn)
File "/usr/lib/python3/dist-packages/tvtk/tests/common.py", line 61, in check_object_garbage_collected
self.assertTrue(object_collected[0])
IndexError: list index out of range

======================================================================
ERROR: test_tvtk_scene_garbage_collected (test_tvtk_scene.TestTVTKScene)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_tvtk_scene.py", line 36, in test_tvtk_scene_garbage_collected
scene_weakref = do()
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_tvtk_scene.py", line 28, in do
scene = TVTKScene()
File "/usr/lib/python3/dist-packages/tvtk/pyface/tvtk_scene.py", line 222, in __init__
self.control = self._create_control(parent)
File "/usr/lib/python3/dist-packages/tvtk/pyface/tvtk_scene.py", line 815, in _create_control
renwin = self._renwin = tvtk.RenderWindow()
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/render_window.py", line 62, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkRenderWindow, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_arrow (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 178, in test_arrow
a = visual.arrow()
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1576, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_box (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 155, in test_box
b = visual.box(size=tuple(sz), pos=pos)
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1414, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_cone (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 86, in test_cone
c = visual.cone()
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 945, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_curve (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 234, in test_curve
c = visual.curve(points=[[0.,0.,0.],[1.,1.,1.]], pos=(1.,1.,1.))
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 574, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_cylinder (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 136, in test_cylinder
c = visual.cylinder(radius=0.5, length=2, pos=(1., 1, 1))
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1248, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_ellipsoid (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 201, in test_ellipsoid
s = visual.ellipsoid(size=(1.0, 1.0, 1.0), pos=(1., 1., 1.))
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1977, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_frame (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 268, in test_frame
s = visual.sphere()
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1093, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_helix (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 248, in test_helix
h = visual.helix(pos=(1., 1.,1.))
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1747, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_ring (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 50, in test_ring
r = visual.ring()
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 761, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
ERROR: test_sphere (test_visual.TestVisual)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_visual.py", line 112, in test_sphere
s = visual.sphere()
File "/usr/lib/python3/dist-packages/tvtk/tools/visual.py", line 1093, in __init__
self.property = self.actor.property
File "/usr/lib/python3/dist-packages/traits/trait_types.py", line 3154, in create_default_value
return klass(*args[1:], **kw)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/actor.py", line 53, in __init__
tvtk_base.TVTKBase.__init__(self, vtk.vtkActor, obj, update, **traits)
File "/usr/lib/python3/dist-packages/tvtk/tvtk_base.py", line 362, in __init__
super(TVTKBase, self).__init__(**traits)
TypeError: super(type, obj): obj must be an instance or subtype of type

======================================================================
FAIL: test_basic_vtk (test_class_tree.TestClassTree)
Basic tests for the VTK module.
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_class_tree.py", line 86, in test_basic_vtk
self.assertEqual(names, expect)
AssertionError: Lists differ: ['object'] != ['object', 'vtkColor3', 'vtkColor4', 'vtkDenseArra[146 chars]or3']

Second list contains 12 additional elements.
First extra element 1:
'vtkColor3'

- ['object']
? ^

+ ['object',
? ^

+ 'vtkColor3',
+ 'vtkColor4',
+ 'vtkDenseArray',
+ 'vtkQuaternion',
+ 'vtkRect',
+ 'vtkSparseArray',
+ 'vtkTuple',
+ 'vtkTypedArray',
+ 'vtkVariantStrictWeakOrderKey',
+ 'vtkVector',
+ 'vtkVector2',
+ 'vtkVector3']

======================================================================
FAIL: test_custom (test_tvtk.TestTVTK)
Test if custom modules can be imported.
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/talbert/debian-packaging/mayavi2/mayavi2/tvtk/tests/test_tvtk.py", line 143, in test_custom
self.assertEqual(r.__class__.__bases__, expect)
AssertionError: Tuples differ: (,) != ()

First tuple contains 1 additional elements.
First extra element 0:

- (,)
+ ()

----------------------------------------------------------------------
Ran 138 tests in 29.704s

FAILED (failures=2, errors=12, skipped=4)
```