<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _create_merge_button(self):
 """Create merge button"""


        bmp = icons["Merge"]
        self.mergetool_id = wx.NewId()
        self.AddCheckTool(self.mergetool_id, "Merge", bmp, bmp,
                          short_help_string=_("Merge cells"))
        self.Bind(wx.EVT_TOOL, self.OnMerge, id=self.mergetool_id)