Raise error when multi line expression is passed for evaluation

[PPakalns]

Using simple_eval method expression like True\nFalse is evaluated to True, False\nTrue to False.

It looks like only the first statement is taken from AST for evaluation.

simpleeval/simpleeval.py

Line 328 in b47858d

return self._eval(ast.parse(expr.strip()).body[0].value)

I suggest that an exception must be raised in case where there are multiple statements to be sure that passed expression is evaluated correctly.

[danthedeckie]

That's a good idea!