





def  SCREAMING_SNAKE_CASE   ( _UpperCAmelCase		,			_UpperCAmelCase				)    ->  float:
    if discount_rate < 0:
        raise ValueError('Discount rate cannot be negative'				)
    if not cash_flows:
        raise ValueError('Cash flows list cannot be empty'				)
    lowerCamelCase__					:   Optional[int]      				=	sum(
        cash_flow / ((1 + discount_rate) ** i) for i, cash_flow in enumerate(_UpperCAmelCase				)				)
    return round(_UpperCAmelCase		,			ndigits=2				)


if __name__ == "__main__":
    import doctest

    doctest.testmod()












_UpperCAmelCase       : List[Any]			     =       {
    """meter""": """m""",
    """kilometer""": """km""",
    """megametre""": """Mm""",
    """gigametre""": """Gm""",
    """terametre""": """Tm""",
    """petametre""": """Pm""",
    """exametre""": """Em""",
    """zettametre""": """Zm""",
    """yottametre""": """Ym""",
}
# Exponent of the factor(meter)
_UpperCAmelCase       : Dict			     =       {
    """m""": 0,
    """km""": 3,
    """Mm""": 6,
    """Gm""": 9,
    """Tm""": 12,
    """Pm""": 15,
    """Em""": 18,
    """Zm""": 21,
    """Ym""": 24,
}


def  SCREAMING_SNAKE_CASE   ( _UpperCAmelCase		,			_UpperCAmelCase		,			_UpperCAmelCase				)    ->  float:
    lowerCamelCase__					:   Dict      				=	from_type.lower().strip('s'				)
    lowerCamelCase__					:   Dict      				=	to_type.lower().strip('s'				)

    lowerCamelCase__					:   Dict      				=	UNIT_SYMBOL.get(_UpperCAmelCase		,			_UpperCAmelCase				)
    lowerCamelCase__					:   str      				=	UNIT_SYMBOL.get(_UpperCAmelCase		,			_UpperCAmelCase				)

    if from_sanitized not in METRIC_CONVERSION:
        lowerCamelCase__					:   List[Any]      				=	(
            F"""Invalid 'from_type' value: {from_type!r}.\n"""
            F"""Conversion abbreviations are: {", ".join(_UpperCAmelCase				)}"""
        )
        raise ValueError(_UpperCAmelCase				)
    if to_sanitized not in METRIC_CONVERSION:
        lowerCamelCase__					:   Optional[Any]      				=	(
            F"""Invalid 'to_type' value: {to_type!r}.\n"""
            F"""Conversion abbreviations are: {", ".join(_UpperCAmelCase				)}"""
        )
        raise ValueError(_UpperCAmelCase				)
    lowerCamelCase__					:   Any      				=	METRIC_CONVERSION[from_sanitized]
    lowerCamelCase__					:   Optional[int]      				=	METRIC_CONVERSION[to_sanitized]
    lowerCamelCase__					:   List[str]      				=	1

    if from_exponent > to_exponent:
        lowerCamelCase__					:   Dict      				=	from_exponent - to_exponent
    else:
        lowerCamelCase__					:   Dict      				=	-(to_exponent - from_exponent)

    return value * pow(10		,			_UpperCAmelCase				)


if __name__ == "__main__":
    from doctest import testmod

    testmod()





