SETUP::
+ sage: from mjo.eja.eja_algebra import JordanSpinEJA
sage: from mjo.eja.eja_utils import _charpoly_sage_input
EXAMPLES::
sage: J = JordanSpinEJA(4,QQ)
- sage: J._charpoly_coefficients()[0]
+ sage: a = J._charpoly_coefficients()
+ sage: a[0]
X1^2 - X2^2 - X3^2 - X4^2
- sage: _charpoly_sage_input("X1^2 - X2^2 - X3^2 - X4^2")
+ sage: _charpoly_sage_input(str(a[0]))
'X[0]**2 - X[1]**2 - X[2]**2 - X[3]**2'
"""