After installation of sagemath, sympy fails to import in python.
(prior to sagemath installation, sympy works as expected)

versions:
sympy-0.7.1-4.fc19.noarch
sagemath-5.9-5.fc19.x86_64

steps to reproduce:
1. enter python
2. enter "import sympy"

the output:

>>> import sympy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/sympy/__init__.py", line 20, in <module>
    from sympy.core import *
  File "/usr/lib/python2.7/site-packages/sympy/core/__init__.py", line 8, in <module>
    from expr import Expr, AtomicExpr
  File "/usr/lib/python2.7/site-packages/sympy/core/expr.py", line 4, in <module>
    from evalf import EvalfMixin
  File "/usr/lib/python2.7/site-packages/sympy/core/evalf.py", line 6, in <module>
    import mpmath.libmp as libmp
  File "/usr/lib/python2.7/site-packages/mpmath/__init__.py", line 6, in <module>
    from .ctx_mp import MPContext
  File "/usr/lib/python2.7/site-packages/mpmath/ctx_mp.py", line 48, in <module>
    from sage.libs.mpmath.ext_main import Context as BaseMPContext
  File "integer.pxd", line 9, in init sage.libs.mpmath.ext_main (sage/libs/mpmath/ext_main.c:27731)
  File "integer.pyx", line 178, in init sage.rings.integer (sage/rings/integer.c:38301)
  File "/usr/lib64/python2.7/site-packages/sage/rings/infinity.py", line 203, in <module>
    import sage.rings.rational
  File "fast_arith.pxd", line 5, in init sage.rings.rational (sage/rings/rational.c:27576)
  File "fast_arith.pyx", line 51, in init sage.rings.fast_arith (sage/rings/fast_arith.c:7830)
  File "integer_ring.pyx", line 66, in init sage.rings.integer_ring (sage/rings/integer_ring.c:11999)
  File "/usr/lib64/python2.7/site-packages/sage/rings/ideal.py", line 36, in <module>
    from sage.interfaces.singular import singular as singular_default
  File "/usr/lib64/python2.7/site-packages/sage/interfaces/singular.py", line 334, in <module>
    from expect import Expect, ExpectElement, FunctionElement, ExpectFunction
  File "/usr/lib64/python2.7/site-packages/sage/interfaces/expect.py", line 51, in <module>
    import cleaner
  File "/usr/lib64/python2.7/site-packages/sage/interfaces/cleaner.py", line 17, in <module>
    import sage.misc.misc as misc
  File "/usr/lib64/python2.7/site-packages/sage/misc/misc.py", line 2082, in <module>
    import sage.server.support
  File "/usr/lib64/python2.7/site-packages/sage/server/support.py", line 19, in <module>
    import sage.misc.sagedoc as sagedoc
  File "/usr/lib64/python2.7/site-packages/sage/misc/sagedoc.py", line 1434, in <module>
    browse_sage_doc = _sage_doc()
  File "/usr/lib64/python2.7/site-packages/sage/misc/sagedoc.py", line 1221, in __init__
    self._base_path = os.path.join(SAGE_DOC, "output/html/en/")
  File "/usr/lib64/python2.7/posixpath.py", line 77, in join
    elif path == '' or path.endswith('/'):
AttributeError: 'NoneType' object has no attribute 'endswith'