title: Type annotation style (to space or not to space)
body: <p>Having the following function:</p>
  
  <pre><code>def foo(x=1):
      print(x)
  </code></pre>
  
  <p>It is clearly stated in <a href="https://www.python.org/dev/peps/pep-0008/" rel="noreferrer">PEP 8</a> that no spaces should be used around the <code>=</code> sign when used to indicate a keyword argument or a default parameter value.</p>
  
  <p>If we want to type-annotate the <code>x</code> parameter. How should we do it?</p>
  
  <pre><code>def foo(x:int=1):
  def foo(x: int=1):
  def foo(x: int = 1):
  </code></pre>
  
  <p>Is there a preferred way? Or even better, is it specified in some PEP? Did not find it in <a href="https://www.python.org/dev/peps/pep-0484/" rel="noreferrer">PEP 484</a>.</p>