title: Expected type 'Number' got 'list[list]' instead
body: <p>I have some nodes who transmit power and I have their positions in a list that I then use to calculate the power receiver from every node to the other so that's what I do:</p>
  
  <pre><code>Node_positions = [[0,100],[100,0],[0,0],[100,100]]
  distances_Ascending = [[]] * len(list(itertools.combinations(Node_positions , 2)))
  Counter = 0
  for p0, p1 in itertools.combinations(Node_positions , 2):
      distances_Ascending[Counter] = (math.sqrt((p0[0] - p1[0]) ** 2 + (p0[1] - p1[1]) ** 2))
  Counter += 1
  
  Powers_Ascending = [[]] * len(list(itertools.combinations(Node_positions , 2)))
  
  counter = 0
  row = 0
  next_no = sheet.nrows - 1
  for elements in range(len(list(itertools.combinations(Node_positions , 2)))):
  Powers_Ascending[elements] = 10 * (math.log10((sheet.cell_value(row, 0) * 1e-3))) - 20 * (
      math.log10((4 * math.pi * distances_Ascending[elements] * 2.4e9) / 3e8))
  counter += 1
  if counter == next_no:
      row += 1
      counter = 0
      next_no -= 1
  </code></pre>
  
  <p>Pycharm for python highlights this part:</p>
  
  <pre><code>(4 * math.pi * distances_Ascending[elements] * 2.4e9) 
  </code></pre>
  
  <p>and says:</p>
  
  <pre><code> Expected type 'Number' got 'list[list]' instead
  </code></pre>
  
  <p>What does that mean?Isn't distances_Ascending already a number which represents the distances between nodes and all the inside the log is a number already?</p>
  
  <p>Where is the problem?</p>