title: Python Gtk3 executable
body: <p>I started using Gtk3 with Python. I have one question: how I could make an executable windows file from my gtk3 python source using pyinstaller, cx_freeze or py2exe? I tried a lot of answers from stack overflow and many other web pages, but none worked. 
  I tried to make it with pyinstaller (I think it could be the easiest way) and my source code looks like:</p>
  
  <pre><code>import gi
  gi.require_version('Gtk', '3.0')
  from gi.repository import Gtk
  
  class ButtonWindow(Gtk.Window):
  
      def __init__(self):
          Gtk.Window.__init__(self, title="Button Demo")
          self.set_border_width(10)
  
          hbox = Gtk.Box(spacing=6)
          self.add(hbox)
  
          button = Gtk.Button.new_with_label("Click Me")
          button.connect("clicked", self.on_click_me_clicked)
          hbox.pack_start(button, True, True, 0)
  
          button = Gtk.Button.new_with_mnemonic("_Open")
          button.connect("clicked", self.on_open_clicked)
          hbox.pack_start(button, True, True, 0)
  
          button = Gtk.Button.new_with_mnemonic("_Close")
          button.connect("clicked", self.on_close_clicked)
          hbox.pack_start(button, True, True, 0)
  
      def on_click_me_clicked(self, button):
          print("\"Click me\" button was clicked")
  
      def on_open_clicked(self, button):
          print("\"Open\" button was clicked")
  
      def on_close_clicked(self, button):
          print("Closing application")
          Gtk.main_quit()
  
  win = ButtonWindow()
  win.connect("delete-event", Gtk.main_quit)
  win.show_all()
  Gtk.main()
  </code></pre>
  
  <p>but I get the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;string&gt;", line 2, in &lt;module&gt;
    File "c:\python34\lib\gi\__init__.py", line 102, in require_version
      raise ValueError('Namespace %s not available' % namespace)
  ValueError: Namespace Gtk not available
  gtk returned -1
  </code></pre>
  
  <p>What shall I do with this or can you please explain me how to make an executable in py2exe or cx_freeze? 
  Please help me! Thanks!</p>