title: How to get itertool.product to generate strings instead of list of chars and then brace each string with additional strings?
body: <p>I don't know much about python data structures but basically I'm generating all permutations of letters :</p>
  
  <pre><code>import, itertools, string    
  k = itertools.product(string.ascii_lowercase, repeat = 2)
  list(k)
  [('a', 'a'), ('a', 'b'), ('a', 'c'), ..., ('z', 'x'), ('z', 'y'), ('z', 'z')]
  </code></pre>
  
  <p>I need to perform 2 operations on the generator <code>k</code> that will preserve it as a generator if possible :</p>
  
  <p>1) Concatenate each list so <code>list(k)</code> would return :</p>
  
  <pre><code>["aa", "ab", ..., "zy", "zz"]
  </code></pre>
  
  <p>2) Brace each string with aditional strings <code>"str1"</code> and <code>"str2"</code> so after step 1) and step 2) <code>list(k)</code> would return :</p>
  
  <pre><code>["str1aastr2", "str1abstr2", ...,"str1zystr2","str1zzstr2"]
  </code></pre>
  
  <p>How to proceed to get a generator that looks like that so I can feed it to scrapy's <code>start_urls</code> ?</p>