title: multiply string by number python
body: <p>So I have a program that takes one argument, an integer num. It is supposed  to return a number that repeats the digits of num 3 times. If the argument is not an integer, the function should return None. </p>
  
  <p>For example:</p>
  
  <p>For input argument "hello!", it should return None, because the input argument is a string.</p>
  
  <p>For input argument "23", it should return None, because the input argument is a string. .</p>
  
  <p>For input argument 12.34, it should return None, because the input argument is a float. .</p>
  
  <p>For input argument 1, it should return 111 or argument 241, it should return 241241241.</p>
  
  <p>I don't know what I'm doing wrong in mine, any help would be appreciated!</p>
  
  <pre><code>def repeat_number(num):
      if num is type(str) and type(float):
          return None
      else:
          return str(num) * 3
  </code></pre>