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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_inches(value, units):
 """ Convert value in inches to given units Parameters value : float Value to be converted units : str Units to convert value to. Must be one of `['in', 'cm', 'mm']`. """

    lookup = {'in': lambda x: x,
              'cm': lambda x: x*2.54,
              'mm': lambda x: x*2.54*10}
    try:
        return lookup[units](value)
    except KeyError:
        raise PlotnineError("Unknown units '{}'".format(units))