File "/nix/store/br51f1j23cnxmbf19yn62rn5pp2rmqdh-sage-src-8.5/src/doc/ca/intro/index.rst", line 492, in doc.ca.intro.index
Failed example:
    solve([x + y == 6, x - y == 4], x, y)
Exception raised:
    Traceback (most recent call last):
      File "/nix/store/mfbhcnzdxiyj831pr3hg1wwh556a6lv3-python-2.7.15-env/lib/python2.7/site-packages/sage/doctest/forker.py", line 671, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/nix/store/mfbhcnzdxiyj831pr3hg1wwh556a6lv3-python-2.7.15-env/lib/python2.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        exec(compiled, globs)
      File "<doctest doc.ca.intro.index[1]>", line 1, in <module>
        solve([x + y == Integer(6), x - y == Integer(4)], x, y)
      File "/nix/store/mfbhcnzdxiyj831pr3hg1wwh556a6lv3-python-2.7.15-env/lib/python2.7/site-packages/sage/symbolic/relation.py", line 1107, in solve
        m = maxima(f)
      File "sage/misc/lazy_import.pyx", line 354, in sage.misc.lazy_import.LazyImport.__call__ (build/cythonized/sage/misc/lazy_import.c:3682)
        return self.get_object()(*args, **kwds)
      File "sage/misc/lazy_import.pyx", line 189, in sage.misc.lazy_import.LazyImport.get_object (build/cythonized/sage/misc/lazy_import.c:2347)
        return self._get_object()
      File "sage/misc/lazy_import.pyx", line 221, in sage.misc.lazy_import.LazyImport._get_object (build/cythonized/sage/misc/lazy_import.c:2584)
        self._object = getattr(__import__(self._module, {}, {}, [self._name]), self._name)
      File "/nix/store/mfbhcnzdxiyj831pr3hg1wwh556a6lv3-python-2.7.15-env/lib/python2.7/site-packages/sage/interfaces/maxima_lib.py", line 113, in <module>
        ecl_eval("(set-pathnames)")
      File "sage/libs/ecl.pyx", line 1326, in sage.libs.ecl.ecl_eval (build/cythonized/sage/libs/ecl.c:10224)
        cpdef EclObject ecl_eval(str s):
      File "sage/libs/ecl.pyx", line 1341, in sage.libs.ecl.ecl_eval (build/cythonized/sage/libs/ecl.c:10163)
        o=ecl_safe_eval(o)
      File "sage/libs/ecl.pyx", line 350, in sage.libs.ecl.ecl_safe_eval (build/cythonized/sage/libs/ecl.c:5221)
        raise RuntimeError("ECL says: {}".format(
    RuntimeError: ECL says: Could not create directory "/build/sage-home/.sage/maxima"
    C library error: "File exists"
**********************************************************************