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 averageValue(self):
      return sum(v[1] for v in self.values) / float(len(self.values))
  
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 5 for calling the ValueLabel obj's underlying member method code with example usage: obj.averageValue() and returns: unknown