z3.z3types.Z3Exception: model is not available
<p>I'm using the latest <code>z3py</code> build release (x64) in Win10 x64, python 2.7 x64.</p>
<p>When I try to call <code>model</code> on this constraint:</p>
<pre><code>(i2 % 59) == (i2 * i10) , (i10 % 43) == ((i2 + i12) % 3) , 4 != (i14 % 28) , 
5 != (i14 % 28) , 6 != (i14 % 28) , 7 != (i14 % 28) , 8 != (i14 % 28) , (i2 
- i12) &gt;= (i12 + i10) , ((i2 - i1) - (i2 * i1)) &gt;= (i1 - 50) , (i12 - i2) &lt; 
(i2 * i12) 
</code></pre>
<p>It throws the following exception:</p>
<pre><code>z3.z3types.Z3Exception: model is not available.
</code></pre>
<p>All the variables (e.g. <code>i2, i10, etc</code> are Integer)</p>
<p>I noted that <code>check</code> produce empty for this constraint.</p>
<p>Does that mean that this constraint is unsat?</p>