title: Get multiplicity of zeros in sympy?
body: <p>I would like to get the multiplicity of zeros as a return value from <code>sympy.solveset</code>.
  For the example below I get <code>zeroes = {0}</code>. I would like to receive something like
  <code>zeroes = {0, 0, 0, 0, 0, 0}</code>. Thanks!</p>
  <pre><code>import sympy
  
  z = sympy.symbols('z')
  zeroes = sympy.solveset(sympy.Eq(z**6, 0), z)
  </code></pre>