code: def _openFile(self):
          
  
          file_types = "Comma Separated Values (*.csv);;Text files (*.txt);;All Files (*)"
          ret = QtGui.QFileDialog.getOpenFileName(self,
                                                  self.tr('open file'),
                                                  filter=file_types)
  
          if isinstance(ret, tuple):
              ret = ret[0] #PySide compatibility maybe?
  
          if ret:
              self._filenameLineEdit.setText(ret)
              self._updateFilename()
docs: Opens a file dialog and sets a value for the QLineEdit widget.
  
          This method is also a `SLOT`.