docs: def simplify_scalar(self, func=sympy.simplify):
          """Simplify all scalar expressions appearing in the Matrix."""
  
          def element_simplify(v):
              if isinstance(v, sympy.Basic):
                  return func(v)
              elif isinstance(v, QuantumExpression):
                  return v.simplify_scalar(func=func)
              else:
                  return v
  
          return self.element_wise(element_simplify)