Error while integrate using algorithm='sympy' (bug)

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Hello! I found next bug:

var('x, y')
integrate(y, y, 0, 8*log(x))
RuntimeError: ECL says: Error executing code in Maxima: defint: upper
limit of integration must be real; found 8*log(x)

Then I decided to use sympy:

var('x, y')
integrate(y, y, 0, 8*log(x), algorithm='sympy')
32*log(x)^2

Nice! But when I replaced 0 --> 0.5 (int --> real):

var('x, y')
integrate(y, y, 0.5, 8*log(x), algorithm='sympy')
AttributeError: 'sage.rings.real_mpfr.RealLiteral' object has no
attribute '_sympy_'

M.... I opened real_mpfr.pyx and added:

1314 def _sympy_(self):
1315     """
1316     Return sympy object.
1317     AUTHORS: #########################
1318     """
1319     import sympy
1320     return(sympy.symplify(float(self)))

(I added line numbers in my code above and remove authors informations (that is about me)) Then I tryed to load:

load('/home/andrei/Programs/Sage/sage-5.10/devel/sage/sage/rings/real_mpfr.pyx')

And there are many-many errors while compilling... Help me please! Thanks.