Merge branch 'pylint' into 'master'

.gitlab-ci.yml

pymbolic/algorithm.py

pymbolic/geometric_algebra/mapper.py

pymbolic/imperative/transform.py

pymbolic/interop/ast.py

pymbolic/interop/common.py

pymbolic/interop/sympy.py

pymbolic/mapper/__init__.py

pymbolic/mapper/constant_converter.py

pymbolic/mapper/constant_folder.py

pymbolic/mapper/differentiator.py

pymbolic/mapper/unifier.py

pymbolic/parser.py

pymbolic/polynomial.py

pymbolic/primitives.py

test/test_pymbolic.py