title: Using variable before assigment error when using lists
body: <p><strong>Using variable 'criteria_names' before assignment pylint(E0601)</strong>.
  This error pops up only for the 'criteria_names' list which is already assigned, but not for the other lists, which are assigned the same way. Any pointers or solutions are very appreciated!</p>
  
  <p>CODE SNIPPET:</p>
  
  <pre><code>data = list()
  lines = list()
  n_vectors = list()
  vectors = list()
  medium_vectors = list()
  classnames = list()
  classes_insert_lines = list()
  vectors_raw = list()
  criteria_names = list()
  
  def DataGet(temp_pulse_file):
      data[:] = []
      n_vectors[:] = []
      vectors[:] = []
      medium_vectors[:] = []
      classnames[:] = []
      classes_insert_lines[:] = []
      vectors_raw[:] = []
      criteria_names[:] = [] #&lt;- this is where the error pops up
  
      with open(temp_pulse_file, "r", encoding='utf-8') as file:
          lines = (file.read()).split("\n")
      file.close()
  
      n = -1
      for i in range(len(lines)):
          data.append(lines[i].split(","))
  
          if data[i][0] == "&gt;":
              n += 1
              classnames.append(data[i][1])
              classes_insert_lines.append(i + 1)
              n_vectors.append(0)
              vectors_raw.append([])
              vectors.append([])
          elif data[i][0] == "#":
              weights = data[i][1:]
          elif data[i][0] == "$":
              criteria_names = list(data[i][1:])
          else:
              n_vectors[n] += 1
              vectors[n].append(data[i])
              vectors_raw[n].append(lines[i])
  
  
      n_elems = len(vectors[0][0])
      classes = len(classnames)
  
      for i in range(classes):
          for j in range(n_vectors[i]):
              for k in range(n_elems):
                  vectors[i][j][k] = float(vectors[i][j][k])
  
      return n_elems, classes, n_vectors, weights, lines, classes_insert_lines, vectors_raw
  
  n_elems, classes, n_vectors, weights, lines, classes_insert_lines, vectors_raw = DataGet(getcurrentdir() + 'db.pulse')
  print(' criteria_names:',criteria_names)
  </code></pre>
  
  <p>When I remove <code>criteria_names[:] = []</code>, no errors whatsoever for the other lists used in the function. Anything helps.</p>