class_docstr: QLabel specifically for displaying numerical values.
  Extends QLabel adding some extra functionality:
  
    - displaying units with si prefix
    - built-in exponential averaging
code: def setFormatStr(self, text):
      self.formatStr = text
      self.update()
  
file_path: pyqtgraph/pyqtgraph/widgets/ValueLabel.py
imports: from time import perf_counter
  from ..None import functions
  from ..Qt import QtWidgets
label_desc: Use image node_id 3 for calling the ValueLabel obj's underlying member method code with example usage: obj.setFormatStr(text) without return types