from __future__ import annotations

import re

_SUFFIX_RE = re.compile(r"(?:_US)?(?:[a-z])?_EQ$")


def _normalise_ticker(raw: str) -> str:
    """Strip T212's exchange-suffix decoration from a ticker.

    T212 tags every ticker with `_EQ`, optionally preceded by a lowercase
    letter ("l" for LSE) or `_US` for a US listing. Peel those off so the
    symbol matches what Schwab / InvestEngine emit.
    """
    return _SUFFIX_RE.sub("", raw)