title: Concatenate the strings using list
body: <p>Write a function to concatenate a list of strings into a single string. For example:
  Input: <code>(["this ", "is ", "a ", "string"])</code> == Output: <code>"this is a string"</code></p>
  
  <p>This is the code I have so far but it always returns with the ", " in the result which I have no idea how to get rid of it. </p>
  
  <pre><code>def concat(strings):
  
      list1 = []
  
      i = 0
  
      while i &lt; len(strings):
  
          list1 += [strings[i]]
          i+=1
  
      return (list1)
  </code></pre>