How to use the psychtoolbox._version.__version__ function in psychtoolbox

outputText += self.getLine(' '*8, "PyGLFW ({})".format(
                glfw.__version__))
        except Exception:
            outputText += self.getLine(' '*8, 'PyGLFW [not installed]')

        # sound related
        try:
            import pyo
            outputText += self.getLine(
                ' '*8, "pyo", ('%i.%i.%i' % pyo.getVersion()))
        except Exception:
            outputText += self.getLine(' '*8, 'pyo [not installed]')
        try:
            import psychtoolbox
            outputText += self.getLine(' '*8, "psychtoolbox ({})".format(
                psychtoolbox._version.__version__))
        except Exception:
            outputText += self.getLine(' '*8, 'psychtoolbox [not installed]')

        # wxpython version
        try:
            import wx
            outputText += self.getLine(' '*8, "wxPython ({})".format(
                wx.__version__))
        except Exception:
            outputText += self.getLine(' '*8, 'wxPython [not installed]')

        # get OpenGL details
        win = visual.Window([100, 100])  # some drivers want a window open first

        outputText += self.getLine("\nOpenGL Info:")
        # # get info about the graphics card and drivers