code: def updateDisplayLabel(self, value=None):
      if value is None:
          value = self.param.value()
      self.sliderLabel.setText(
          self.prettyTextValue(self.slider.value())
      )
      value = str(value)
      if self._suffix is None:
          suffixTxt = ""
      else:
          suffixTxt = f" {self._suffix}"
      self.displayLabel.setText(value + suffixTxt)
  
file_path: pyqtgraph/pyqtgraph/parametertree/parameterTypes/slider.py
imports: import numpy
  from ...Qt import QtCore, QtWidgets
  from ..Parameter import Parameter
  from .basetypes import Emitter, WidgetParameterItem
label_desc: Use image node_id 2 for calling the SliderParameterItem obj's underlying member method code with example usage: obj.updateDisplayLabel(value) without return types