def is_valid_hgt(value: str) -> bool:
    """
    Return if value is a valid hgt (height).

    Parameter
    ---------
    value: str
        a height in 'cm' or 'in'.

    Return
    ------
    bool
        True if height is valid, False othewise.
    """
    height, unit = value[:-2], value[-2:]
    if not all((char.isdigit() for char in height)):
        return False
    if unit == "in":
        return 59 <= int(height) <= 76
    if unit == "cm":
        return 150 <= int(height) <= 193

    return False