nestedInterfaces.py

from myhdl import Signal, instances


class A_Interface:
  def __init__(self):
    a = Signal(bool(0)) 
    
class B_Interface:
  def __init__(self):
    b = Signal(bool(0))
  
class nested_Interface:
  def __init__(self):
    c = A_Interface()
    d = B_Interface()
    
@block 
def top(nested_Interface1):
  sub1Inst = sub1(nested_Interface1.c)
  sub2Inst = sub2(nested_Interface1.d)
  
  return instances()