title: Should I pass sympy symbols to functions?
body: <p>Is there any disadvantage of not passing sympy symbols to functions?</p>
  
  <pre><code>def compute(alpha,a): #or def compute(a)
      return 3*alpha+a
  
  alpha = sympy.symbols("alpha")
  expr = compute(alpha,3)
  </code></pre>
  
  <p>I don't have to pass <code>alpha</code> to <code>compute()</code> (I assume because it's a global variable), and right now, I think it makes the code better readable when I leave it out.
  Is this considered bad design? I suppose this is a general "what to do with global variables in python" question, as has been asked <a href="https://stackoverflow.com/questions/10234901/python-functions-pass-global-variables-if-only-accessing-them">here</a>, but the answers said it would depend on the specific usecase.</p>
  
  <p>I still have to create the <code>alpha</code> symbol before I call that function, it's just not obvious if i do not include it.</p>