title: Generate many SymPy expressions using the same symbols
body: <p>I want to create many (more than 400) SymPy expressions using the same set of symbols.  The expressions would look like:</p>
  
  <pre><code>z_1_8 = k1 + k2 + kuni + k4 + k7
  z_2_9_0 = k2 + k8 + k1 + k6
  z_3_1_10 = k3 + kbi + k2 + k7
  </code></pre>
  
  <p>The names 'z_1_8' would be generated from a list, where each member of the list contains the numbers that name each expression.  Likewise the symbols would also come from a list in which each member contains a list of the symbols as strings - <code>'k1'</code>, <code>'k2'</code> etc - for each expression to be generated.</p>
  
  <pre><code>list_to_generate_expression_names = [[1, 8], [2, 9, 0], [3, 1, 10],...]
  list_to_generate_expressions = [['k1', 'k2','kuni','k4','k7'], ['k2', 'k8', 'k1', 'k6'], ['k3', 'kbi', 'k2', 'k7']]
  </code></pre>
  
  <p>What might be a way to do this?</p>