code: def multiplication_rule(self, units):
      non_null = [u for u in units if u]
      if len(non_null) > 1:
          return NotImplemented
      return non_null[0]
  
imports: import math
  from packaging.version import parse
  import numpy
  import matplotlib.ticker
  import matplotlib.units
label_desc: Use image node_id 2 for calling the UnitResolver obj's underlying member method code with example usage: obj.multiplication_rule(units) and returns: non_null, NotImplemented