Set shell styles font

def set_font(self, font):
        """Set shell styles font"""
        self.setFont(font)
        self.set_pythonshell_font(font)
        cursor = self.textCursor()
        cursor.select(QTextCursor.Document)
        charformat = QTextCharFormat()
        charformat.setFontFamily(font.family())
        charformat.setFontPointSize(font.pointSize())
        cursor.mergeCharFormat(charformat)