# Revision history [back]

### How to get sage to keep the same form as an expression from sympy?

I have this expression:

$$-\frac{2}{3} t_{1} + \frac{2}{3} y_{1}$$

and would like to rewrite it as follows:

$$\frac{2}{3} (-t_1 + y_1)$$

Using sympy, I can get something close:

import sympy as sp

var('y1 t1')
expr1 = -2/3*t1 + 2/3*y1
sp.factor(sp.sympify(expr1))


This gives:

𝟸*(⎯𝚝𝟷+𝚢𝟷)/𝟹


But when I convert it back to Sage:

sp.factor(sp.sympify(expr1))._sage_()


The result reverts to expr1.

How can I get the call to _sage_() not do any rewrites on the sympy expression?