title: Why do parentheses appear to cause evaluation in Python?
body: <p>I see in this accepted <a href="https://stackoverflow.com/a/6076304/93190">answer</a> to a question about lambda functions in Python, it seems that the <em>parentheses</em> around what was, in the OP's question, a lambda function <em>definition</em>, will cause it to be <em>evaluated</em>. Perhaps standard behavior across languages (as I see similar in Powershell, <a href="https://stackoverflow.com/a/13188873/93190">here</a>)? And <a href="https://stackoverflow.com/a/8900189">this answer about tuples</a> may figure in somehow. It all feels familiar. But can someone provide the link to Python documentation (or succinct text that should be there even if it's not there) explaining why parentheses cause evaluation in Python?</p>
  
  <p>Your answer will help me digest the original answer about lambda functions in list comprehensions.</p>