code: def _(a, b):
      if b.is_subset(S.Reals):
          # treat a subset of reals as a complex region
          b = ComplexRegion.from_real(b)
  
      if b.is_ComplexRegion:
          # a in rectangular form
          if (not a.polar) and (not b.polar):
              return ComplexRegion(Union(a.sets, b.sets))
          # a in polar form
          elif a.polar and b.polar:
              return ComplexRegion(Union(a.sets, b.sets), polar=True)
      return None
  
imports: from sympy.core.singleton import S
  from sympy.core.sympify import sympify
  from sympy.functions.elementary.miscellaneous import Min, Max
  from sympy.sets.sets import EmptySet, FiniteSet, Intersection, Interval, ProductSet, Set, Union, UniversalSet
  from sympy.sets.fancysets import ComplexRegion, Naturals, Naturals0, Integers, Rationals, Reals
  from sympy.multipledispatch import Dispatcher
label_desc: Use image node_id 8 for calling a global function with example usage: _(a, b) and returns: None, ComplexRegion, ComplexRegion