title: Error: ( : 1) Invalid number of arguments for python-fu command line execution
body: <p>I have added the following python script to <em>/usr/lib/gimp/2.0/plug-ins</em> folder</p>
  
  <pre><code>#!/usr/bin/python
  
  from gimpfu import *
  
  def scale(imageName):
      pass
  
  register(
      "my",
      "",
      "",
      "",
      "",
      "2017",
      "&lt;Image&gt;/Image/Hi..",
      "RGB*, GRAY*",
      [(PF_STRING, 'file_name', 'file_name', 'logo.png')],
      [],
      scale)
  
  main()
  </code></pre>
  
  <p>Running it via </p>
  
  <pre><code>gimp --no-interface -b '(python-fu-my RUN-NONINTERACTIVE "logo.png")' -b '(gimp-quit 0)'
  </code></pre>
  
  <p>returns</p>
  
  <blockquote>
    <p>batch command experienced an execution error: Error: ( : 1) Invalid
    number of arguments for python-fu-my (expected 4 but
    received 2)</p>
  </blockquote>
  
  <p>In Gimp's Procedure Browser there are 4 parameters indeed, but it should not expect them if procedure is run via command line, should it?</p>
  
  <p><a href="https://i.stack.imgur.com/k8efy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/k8efy.png" alt="Parameters"></a></p>
  
  <p>I followed the <a href="https://www.gimp.org/docs/python/" rel="nofollow noreferrer">docs</a>.
  What is wrong?</p>