title: Create a function to determine if a number is even
body: <p>As the home assignment, I have two code cells. In the first one, I need to write a code, while the second check the written function (it was made by a professor)</p>
  <p>[Cell1]</p>
  <pre><code>def is_even_number(num):
      '''
      Returns True if num is even number, otherwise False
      
      Parameters
      ----------
      num : an integer
      
      Returns
      -------
      True if num is even number, otherwise False
      '''
      # YOUR CODE HERE
      while num:
          if num % 2 == 0:
              return True
          elif num % 2 != 0:
              return False
  </code></pre>
  <p>[Cell2]</p>
  <pre><code>assert_true(is_even_number(2), msg='2 is an even number.')
  assert_true(not is_even_number(1), msg='1 is not an even number')
  </code></pre>
  <p>As a result of run Cell2, I see the message NameError: name 'assert_true' is not defined</p>