title: str.split(' ') giving me "ValueError: empty separator" for a sentence in the form of a string
body: <p>TLDR:
  If you don't specify a character for <code>str.split</code> to split by, it defaults to a space or tab character. My error was due to the fact that I did not have a space between my quotes.</p>
  
  <hr>
  
  <p>In case you were wondering, the separator I specified is a space:</p>
  
  <pre><code>words = stuff.split(" ")
  </code></pre>
  
  <p>The string in question is <code>This is an example of a question.</code>
  I also tried <code>#</code> as the separator and put <code>#</code>'s into my sentence and got the same error.</p>
  
  <p><strong>Edit: Here is the complete block</strong></p>
  
  <pre><code>def break_words(stuff):
  """This function will break up words for us."""
      words = stuff.split(" ")
      return words
  sentence = "This is an example of a sentence."
  print break_words(sentence)
  </code></pre>
  
  <p>When I run this as py file, it works.
  but when I run the interpreter, import the module, and type:
  <code>sentence = "This is an example of a sentence."</code>
  followed by <code>print break_words(sentence)</code></p>
  
  <p>I get the above mentioned error.</p>
  
  <p>And yes, I realise that this is redundant, I'm just playing with functions.</p>
  
  <p><strong>Edit 2: Here is the entire traceback:</strong></p>
  
  <pre><code>Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  File "ex25.py", line 6, in break_words
  words = stuff.split(' ')
  </code></pre>
  
  <p><strong>Edit 3: Well, I don't know what I did differently, but when I tried it again now, it worked:</strong></p>
  
  <pre><code>&gt;&gt;&gt; s = "sdfd dfdf ffff"
  &gt;&gt;&gt; ex25.break_words(s)
  ['sdfd', 'dfdf', 'ffff']
  &gt;&gt;&gt; words = ex25.break_words(s)
  &gt;&gt;&gt;
  </code></pre>
  
  <p>As you can see, no errors.</p>