How to pretty print to a file in sympy?

Question

Suppose I have the following code:

import sympy as sp
from sympy.physics.quantum import TensorProduct

s=sp.eye(2)
a=TensorProduct(s*x,TensorProduct(s,s)).subs(x,x**2+2*x+1)
sp.pprint(a)

The code will generate an output with a limited widths (which I hate):

My questions are:

1. Why there is a width limit while my window has enough space and how to change it?
2. How to print such an output to a file?

Answer 1

For python>=3.4,

from contextlib import redirect_stdout
import sympy as sp
from sympy.physics.quantum import TensorProduct

s = sp.eye(2)
x = sp.symbols('x')
a = TensorProduct(s*x, TensorProduct(s, s)).subs(x, x**2+2*x+1)

with open('data.txt', 'w') as f:
    with redirect_stdout(f):
        sp.pprint(a, wrap_line=False)

.