title: How to determine if the variable is a function in Python?
body: <p>Since functions are values in Python, how do I determine if the variable is a function?</p>
  
  <p>For example:</p>
  
  <pre><code>boda = len   # boda is the length function now
  if ?is_var_function(boda)?:
    print "Boda is a function!"
  else:
    print "Boda is not a function!"
  </code></pre>
  
  <p>Here hypothetical <code>?is_var_function(x)?</code> should return true if <code>x</code> is a callable function, and false if it is not.</p>