WXPYTHON (NameError: global name 'myFrame' is not defined - python-2.7

Question

Below is screenshot of the error. Why does it happen?

Answer 1

This is probably what you are trying to achieve. Although when posting to StackOverflow you should cut and paste your code into the question and not put it in a link, especially a link that is an image.
Few people will make the effort to help, if you make it difficult for them to do so.
import wx
class MyApp(wx.App):
def OnInit(self):
self.frame = MyFrame()
self.SetTopWindow(self.frame)
return True
class MyFrame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self,None, title="Window", pos = (100,150), size =(250,200))
menu = wx.Menu()
menu.Append(1,'&About')
menu.AppendSeparator()
menu.Append(2,'E&xit')
menuBar = wx.MenuBar()
menuBar.Append(menu,'&File')
self.Bind(wx.EVT_MENU, self.OnAbout, id=1)
self.Bind(wx.EVT_MENU, self.OnExit, id=2)
self.SetMenuBar(menuBar)
self.Layout()
self.Show()
def OnExit(self, evt):
self.Destroy()
def OnAbout(self, evt):
print("This is MyFrame")
if __name__ == "__main__":
app = MyApp()
app.MainLoop()

Answer 2

I can't figure out how you even ran that code because your if __name__ == '__main__' and you main method are indented inside your myFrame class. Try out-indenting it I mean your end of code should be like:
def main():
app = myApp()
app.MainLoop()
if __name__ == '__main__':
main()
also, your naming convention is not pythonic.
Python recommends UpperCamelCase for class names, CAPITALIZED_WITH_UNDERSCORES for constants, and lowercase_separated_by_underscores for other names.