title: I am having a problem with my code on Sieve of Eratosthenes
body: <p>See my code below. I keep getting an error code, and I don't understand what it means too. Where in the code can I look?</p>
  <pre><code>def list_true(n):
      return [False for x in range(2)] + [x for x in range (2, n+1)]
  
  assert len(list_true(20)) == 21
  assert list_true(20)[0] is False
  assert list_true(20)[1] is False
  
  
  def mark_false(bool_list, p):
      mark_false = []
      for x in bool_list:
          if x/p == 1:
              mark_false.append(True)
          elif x % p == 0:
              mark_false.append(False)
          else:
              mark_false.append(True)
      return mark_false
  
  assert mark_false(list_true(6), 2) == [False, False, True, True, False, True, False]
  
  def find_next(bool_list, p):
      x = 0
      cleared = False
      for bool in bool_list:
          if cleared:
              if bool:
                  return x
          if x == p and bool:
              cleared = True
          x += 1
      return None
  
  assert find_next([True, True, True, True], 2) == 3
  assert find_next([True, True, True, False], 2) is None
  
  def prime_from_list(bool_list):
      y = [x for x, i in enumerate(bool_list) if i]
      prime_from_list = []
      for element in bool_list:
          if element == True:
              return y
      return prime_from_list
  
  assert prime_from_list([False, False, True, True, False]) ==  [2, 3]
  
  def sieve(n):
      bool_list = list_true(n)
      p = 2
      while p is not None:
          bool_list = mark_false(bool_list, p)
          p = find_next(bool_list, p)
      return prime_from_list(bool_list)
  </code></pre>
  <p>Then I get an error message after the below code.</p>
  <pre><code>assert sieve(1000) == get_primes(0, 1000)
  --------------------------------------------------------------------------
  AssertionError                            Traceback (most recent call last)
  &lt;ipython-input-50-c49169fabbae&gt; in &lt;module&gt;()
  ----&gt; 1 assert sieve(1000) == get_primes(0, 1000)
  
  AssertionError: 
  </code></pre>
  <p>Why am I getting the error and is there a possible way I can amend it?</p>