That fundamentally misunderstands the problem in multiple ways: * this is still during lexing, not yet to parsing * there are multiple valid token sequences t

That fundamentally misunderstands the problem in multiple ways: * this is still during lexing, not yet to parsing * there are multiple valid token sequences that vary only with a single character at the start of the file. This is very common with Python multi-line strings in particular, since they are widely used as docstrings.