title: sympy's ConditionSet object not iterable
body: <p>I would like to generate a simple set based on a condition to mimic set builder notation, and then enumerate its contents. I tried the following based on an example <a href="https://docs.sympy.org/latest/modules/sets.html" rel="nofollow noreferrer">in the docs</a>:</p>
  <pre><code>from sympy import Symbol, S, ConditionSet
  from sympy.abc import x
  
  new_set = ConditionSet(x, x&lt;7, S.Naturals)
  iterable = iter(new_set)
  print(&quot;done&quot;)
  </code></pre>
  <p>When I run this I get an error:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;test.py&quot;, line 5, in &lt;module&gt;
      iterable = iter(new_set)
  TypeError: 'ConditionSet' object is not iterable
  </code></pre>
  <p>Why is it that I cannot enumerate the <code>ConditionSet</code> object? It has finite contents so I would assume this should be possible?</p>