title: AttributeError: 'float' object has no attribute 'shape'
body: <p>I'm trying to get the solution(W2) of a equation, which include np.cov, using python sympy.Solvers, but get a AttributeError: 'float' object has no attribute 'shape'. </p>
  
  <p><img src="https://i.stack.imgur.com/20EHT.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/diK0n.png" alt="enter image description here"></p>