def METHOD_NAME(self):
    val, selected = QtWidgets.QInputDialog.getDouble(
        self,
        "Core effective area",
        "Set core cross section area length in mm\N{SUPERSCRIPT TWO}",
        value=self.coreArea,
        decimals=2,
    )
    if not selected:
        return
    if not (self.fixedValues and val >= 0):
        self.coreArea = val
    if self.fixedValues:
        self.update()