title: Usage for lru cache in functools
body: <p>I want to use lru_cache in my code, however, I get this error:</p>
  
  <pre><code>NameError: name 'lru_cache' is not defined
  </code></pre>
  
  <p>I do have an import functools in my code but that does not help</p>
  
  <p>Example code is here:</p>
  
  <pre><code>https://docs.python.org/3/library/functools.html
  
  @lru_cache(maxsize=None)
  def fib(n):
      if n &lt; 2:
          return n
      return fib(n-1) + fib(n-2)
  </code></pre>