"""杠杆口径 v1：杠杆 = 标的指数 ÷ 期权卖一（ask）。"""

from __future__ import annotations

LEVERAGE_FORMULA_VERSION = "1.0"


def option_leverage(index_px: float, ask: float | None) -> float | None:
    """index_px / ask；ask 无效时返回 None。"""
    if index_px is None or index_px <= 0:
        return None
    if ask is None or ask <= 0:
        return None
    return float(index_px) / float(ask)