title: Sum of all numbers in a file
body: <p>I have been fiddling round with this code for ages and cannot figure out how to make it pass the doctests. the output is always 1000 less than the corrects answer. is there a simple way to change this code so that it gives the desired output ??
  my code is:</p>
  
  <pre><code>def sum_numbers_in_file(filename):
      """
      Return the sum of the numbers in the given file (which only contains
      integers separated by whitespace).
      &gt;&gt;&gt; sum_numbers_in_file("numb.txt")
      19138
      """
      f = open(filename)
      m = f.readline()
      n = sum([sum([int(x) for x in line.split()]) for line in f])
      f.close()
      return n
  </code></pre>
  
  <p>the values in the file are:</p>
  
  <pre><code>1000 
  15000 
  2000 
  1138
  </code></pre>