title: Type Error thrown during Multiprocessing while trying to append results to a shared list
body: <p>I am trying to parallelize a function that appends results to a shared list using the multiprocessing library and keep getting the following error:</p>
  
  <p><code>TypeError: '&lt;=' not supported between instances of 'ListProxy' and 'Int'</code></p>
  
  <p>I think the part that is tripping me up is the appending to append each result to a shared list. If I take this part of the code out, the script runs fine. However, the whole point in running this script is to append a lot of things to one list.</p>
  
  <p>A google search tells me that this error is caused because i am "comparing a sequence to an integer". I get what the error is saying, but I don't know how to interpret it in terms of the multiprocessing library</p>
  
  <p>I am not sure what I am doing wrong here. Could someone please point me in the right direction?</p>
  
  <p>Below is a simplified version of the code I am trying to use</p>
  
  <pre><code>import lasio
  import glob 
  from multiprocessing import Pool, Process, Manager
  
  
  #generates a list of filepaths to be fed to the parralelization
  wellfiles = []
  for file in glob.glob(....filedierctory...//*):
      wellfiles.append(file)
  
  
  def process_file(filepath,L):
      #read the file
      las = lasio.read(filepath)
      #extract the value I want from the file
      uwi = las.well[11].value
      #print the value
      print(uwi)
      #append the value to a shared list. THIS IS WHERE I THINK THINGS ARE FAILING
      L.append(uwi)
  
  
  if __name__ == '__main__':
      with Manager() as manager:
          L = manager.list()
          p = Pool(5)
          p.map(process_file, wellfiles,L)
          p.join()
  </code></pre>
  
  <p>Please let me know if I can clarify anything</p>