old_contents: from .quantity import Quantity
  
  class CurrentMixin(Quantity):
  
      quantity = 'current'
      quantity_label = 'Current'
      units = 'A'
      is_current = True
  
      def cpt(self):
          from .oneport import I
          
          return I(self)
  
      
      
  
new_contents: from .quantity import Quantity
  
  class CurrentMixin(Quantity):
  
      quantity = 'current'
      quantity_label = 'Current'
      units = 'A'
      is_current = True
  
      def cpt(self):
          from .oneport import I, Idc, Iac
          
          if self.is_dc:
              return Idc(self.expr)
          elif self.is_ac:
              p = self.as_phasor()
              return Iac(p.expr, omega=p.omega)            
          
          return I(self.expr)
  
      
      
  
      
      
  
subject: Create Iac and Idc