/usr/lib/python2.7/dist-packages/sage/calculus/ is in sagemath-common 8.1-7ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/sage/calculus/__init__.py
/usr/lib/python2.7/dist-packages/sage/calculus/all.py
/usr/lib/python2.7/dist-packages/sage/calculus/calculus.py
/usr/lib/python2.7/dist-packages/sage/calculus/desolvers.py
/usr/lib/python2.7/dist-packages/sage/calculus/functional.py
/usr/lib/python2.7/dist-packages/sage/calculus/functions.py
/usr/lib/python2.7/dist-packages/sage/calculus/interpolation.pxd
/usr/lib/python2.7/dist-packages/sage/calculus/ode.pxd
/usr/lib/python2.7/dist-packages/sage/calculus/predefined.py
/usr/lib/python2.7/dist-packages/sage/calculus/test_sympy.py
/usr/lib/python2.7/dist-packages/sage/calculus/tests.py
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/__init__.py
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/all.py
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/dft.py
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/dwt.pxd
/usr/lib/python2.7/dist-packages/sage/calculus/transforms/fft.pxd
/usr/lib/python2.7/dist-packages/sage/calculus/wester.py