the copy of a bitmap

wxPython Users
1

Hello,
if I want to make the copy of a list i do:
    a = list
  b = a[:]
how to make the copy of bitmap instance
  bitmap = wxImage......or any bitmap
  bmp1 = bitmap
  bmp2 = bitmap
now bmp1 = bmp2, i want to bmp2 be a separate instance

Thanks in adv.