title: Using Recursion / Getting 'None' attached to my output
body: <p>for some reason I cannot seem to wrap my head around returning things properly. I am trying to get strings to become acronyms using recursion (ignore that my code is sloppy lol) but it just attaches None to the end of my desired output!</p>
  <p>How can I fix this? Again, recursion is necessary for this problem!</p>
  <pre><code>def recAbbrev(lst):
      'return a single string with the first character of all the strings in a list combined and capitalized.'
      if len(lst)== [] :
          return 0
      
      if len(lst)&gt;0:
          if type(lst[0])==list:
              return 1 + recAbbrev(lst[0])
          else:
              acronym = &quot;&quot;
              letter = &quot;&quot;
              letter = letter + lst[0][:1]
              letter = letter.upper()
              acronym = acronym + letter
              print(acronym, end = '')  
              return recAbbrev(lst[1:])
             
  </code></pre>
  <p>Output</p>
  <pre><code>Traceback (most recent call last):
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-s.py&quot;, line 80, in &lt;module&gt;
      print(recEvenNumbers(['c','a','t',' ' ,0,'h',1,'a',2,'t',100]))
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-.py&quot;, line 49, in recEvenNumbers
      return recEvenNumbers(lst[1:])
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-s.py&quot;, line 49, in recEvenNumbers
      return recEvenNumbers(lst[1:])
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-As.py&quot;, line 49, in recEvenNumbers
      return recEvenNumbers(lst[1:])
    [Previous line repeated 1 more time]
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-s.py&quot;, line 47, in recEvenNumbers
      return recEvenNumbers(evens)
    File &quot;C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\csc242hw7-.py&quot;, line 44, in recEvenNumbers
      elif type(lst[0]) == int:
  TypeError: 'int' object is not subscriptable
  </code></pre>
  <p>Starting recAbbrev
  None
  CPUNone
  RAMNone
  Starting recEvenNumbers</p>
  <pre><code>
  thank you!
  </code></pre>