title: object of type 'NoneType' has no len(), but I'm pretty sure my object is a valid list
body: <p>The following module keeps failing for me, telling me that an object of type 'NoneType' has no len(), but it seems that the object being passed is a list, not an object of type 'NoneType'. I include the module and the output below.</p>
  
  <pre><code>def Purge_Polyploid_MisScores(dictOfLists):
    #print "dict getting passed to Purge_Polyploid_MisScores function", dictOfLists
    for x in dictOfLists.keys():
      for y in range (0, len(dictOfLists[x])):
        print "x", x, " and y", y
        print dictOfLists[x][y]
        #if not dictOfLists[x][y]:
          #print "error at ",x,dictOfLists[str(int(x)-1)][0]
        if len(dictOfLists[x][y])&gt;3:
          try:
            dictOfLists[x][y]=dictOfLists[x][y].remove('**')
          except:
            for z in dictOfLists[x][y]:
              if dictOfLists[x][y].count(z)&gt;2:
                print "removed ",z," at dictOfLists[",x,"][",y,"]", dictOfLists[x][y]
                dictOfLists[x][y].remove(z)
                #I think this produces an error: dictOfLists[x][y]=dictOfLists[x][y].remove(z)
                print "now, it looks like", dictOfLists[x][y]
          if len(dictOfLists[x][y])&gt;3:
            print "The Length is still greater than 3! at dictOfLists[",x,"][",y,"]", dictOfLists[x][y]
  
            #print "the reason you have a polyploid is not a mis-score"
            #print "dictOfLists[",x,"][",y,"]",dictOfLists[x][y]
        print "Reached the end of the loop"
    return dictOfLists
  </code></pre>
  
  <p>Error/output preceding the error:</p>
  
  <pre><code>x 449  and y 100
  ['Yellow submarine', '273', '273']
  Reached the end of the loop
  x 449  and y 101
  ['Heartland', '250', '250', '250']
  removed  250  at dictOfLists[ 449 ][ 101 ] ['Heartland', '250', '250', '250']
  now, it looks like ['Heartland', '250', '250']
  Reached the end of the loop
  x 449  and y 102
  ['Julia', '116', '119', '**']
  Traceback (most recent call last):
    File "fast_run.py", line 11, in &lt;module&gt;
      sample_names_list_e1_keys_as_numbers_e2=transpose.combine_allele_report_pipeline_dict(pipeline_directory, keeplist_address, rejected_samples_address)
    File "/Users/markfisher/transpose.py", line 887, in combine_allele_report_pipeline_dict
      samples=Purge_Polyploid_MisScores(samples)
    File "/Users/markfisher/transpose.py", line 1332, in Purge_Polyploid_MisScores
      if len(dictOfLists[x][y])&gt;3:
  TypeError: object of type 'NoneType' has no len() 
  </code></pre>
  
  <p>In other words, <code>['Julia', '116', '119', '**']</code> seems to be failing at if <code>len(['Julia', '116', '119', '**'])&gt;3</code>, and I have no idea why.</p>
  
  <p>I hope that I've equipped you guys with enough to see my error! Thanks!</p>