class_docstr: An output target you can connect action signals to to implement
  behaviour.
class_docstr_tok: ["An","output","target","you","can","connect","action","signals","to","to","implement","behaviour","."]
docstr: Attach a finish handler.
  
  For libvips 8.13 and later, this method is deprecated in favour of
  :meth:`on_end`.
docstr_tok: ["Attach","a","finish","handler",".","For","libvips","8.13","and","later",",","this","method","is","deprecated","in","favour","of",":","meth",":","`","on_end","`","."]
code: def on_finish(self, handler):
      """Attach a finish handler.
  
      For libvips 8.13 and later, this method is deprecated in favour of
      :meth:`on_end`.
  
      """
  
      self.signal_connect("finish", handler)
  
file_path: pyvips/pyvips/vtargetcustom.py
imports: from __future__ import division
  import logging
  import pyvips
  from pyvips import ffi, vips_lib, at_least_libvips
label_desc: Use image node_id 6 for calling the TargetCustom obj's underlying member method code with example usage: obj.on_finish(handler) without return types