code: def _create_B(self,Y):
                   
  
          Z = self._create_Z(Y)
          return np.dot(np.dot(Y,np.transpose(Z)),np.linalg.inv(np.dot(Z,np.transpose(Z))))
docs: Creates OLS coefficient matrix
  
          Parameters
          ----------
          Y : np.array
              The dependent variables Y
  
          Returns
          ----------
          The coefficient matrix B