"""Misc helper functions"""

import logging
from typing import Dict, Optional


def convert_units(
    value: float, unit: str, unit_conversions: Dict[str, float]
) -> Optional[float]:
    """Convert a given value and unit into a different unit.
    Round the returned value to 2 significant decimals
    If unrecognized unit, return None"""
    try:
        conversion = unit_conversions[unit]
    except KeyError:
        logging.error("unrecognized unit: %s", unit)
        return None
    return round(value * conversion, 2)