Logical `and` instead of bitwise `&`.

[UriyaHarpeness]

These two lines contain an incorrect form of and, needs to be &.

py-expression-eval/py_expression_eval/__init__.py

Line 468 in fd18b6f

if expected and self.OPERATOR == 0:

py-expression-eval/py_expression_eval/__init__.py

Line 475 in fd18b6f

if expected and self.PRIMARY == 0: