Mayavi import error

      File "/usr/local/lib/python2.7/dist-packages/mayavi-4.4.3-py2.7-linux-x86_64.egg/mayavi/mlab.py", line 27, in <module>
        from mayavi.tools.camera import view, roll, yaw, pitch, move
      File "/usr/local/lib/python2.7/dist-packages/mayavi-4.4.3-py2.7-linux-x86_64.egg/mayavi/tools/camera.py", line 25, in <module>
        from engine_manager import get_engine
      File "/usr/local/lib/python2.7/dist-packages/mayavi-4.4.3-py2.7-linux-x86_64.egg/mayavi/tools/engine_manager.py", line 12, in <module>
        from mayavi.preferences.api import preference_manager
      File "/usr/local/lib/python2.7/dist-packages/mayavi-4.4.3-py2.7-linux-x86_64.egg/mayavi/preferences/api.py", line 4, in <module>
        from preference_manager import preference_manager
      File "/usr/local/lib/python2.7/dist-packages/mayavi-4.4.3-py2.7-linux-x86_64.egg/mayavi/preferences/preference_manager.py", line 29, in <module>
        from traitsui.api import View, Group, Item
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/api.py", line 36, in <module>
        from .editors.api import ArrayEditor
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/editors/__init__.py", line 23, in <module>
        from .api import ArrayEditor
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/editors/api.py", line 24, in <module>
        from .code_editor import CodeEditor
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/editors/code_editor.py", line 36, in <module>
        class ToolkitEditorFactory ( EditorFactory ):
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/editors/code_editor.py", line 48, in ToolkitEditorFactory
        mark_color = Color( 0xECE9D8 )
      File "/usr/local/lib/python2.7/dist-packages/traits-4.5.0-py2.7-linux-x86_64.egg/traits/traits.py", line 489, in __call__
        return self.maker_function( *args, **metadata )
      File "/usr/local/lib/python2.7/dist-packages/traits-4.5.0-py2.7-linux-x86_64.egg/traits/traits.py", line 1203, in Color
        return ColorTrait( *args, **metadata )
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/toolkit_traits.py", line 7, in ColorTrait
        return toolkit().color_trait( *args, **traits )
      File "/usr/local/lib/python2.7/dist-packages/traitsui-5.0.0-py2.7.egg/traitsui/toolkit.py", line 125, in toolkit
        ETSConfig.toolkit = toolkit_name
      File "/usr/local/lib/python2.7/dist-packages/traits-4.5.0-py2.7-linux-x86_64.egg/traits/etsconfig/etsconfig.py", line 213, in _set_toolkit
        "already been set to %s" % (toolkit, self._toolkit)
    ValueError: cannot set toolkit to wx because it has already been set to qt4