code: def vtableEqual(a, objectStart, b):
      
  
      N.enforce_number(objectStart, N.UOffsetTFlags)
  
      if len(a) * N.VOffsetTFlags.bytewidth != len(b):
          return False
  
      for i, elem in enumerate(a):
          x = encode.Get(packer.voffset, b, i * N.VOffsetTFlags.bytewidth)
  
          # Skip vtable entries that indicate a default value.
          if x == 0 and elem == 0:
              pass
          else:
              y = objectStart - elem
              if x != y:
                  return False
      return True
docs: vtableEqual compares an unwritten vtable to a written vtable.