<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def choose_meas_file(self, event=None):
 """ Opens a dialog allowing the user to pick a measurement file """

        dlg = wx.FileDialog(
            self, message="Please choose a measurement file",
            defaultDir=self.WD,
            defaultFile="measurements.txt",
            wildcard="measurement files (*.magic,*.txt)|*.magic;*.txt",
            style=wx.FD_OPEN | wx.FD_CHANGE_DIR
        )
        if self.show_dlg(dlg) == wx.ID_OK:
            meas_file = dlg.GetPath()
            dlg.Destroy()
        else:
            meas_file = ''
            self.data_model = 2.5
            dlg.Destroy()
        return meas_file