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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 _get_conversion_factor(old_units, new_units, dtype):
 """ Get the conversion factor between two units of equivalent dimensions. This is the number you multiply data by to convert from values in `old_units` to values in `new_units`. Parameters old_units: str or Unit object The current units. new_units : str or Unit object The units we want. dtype: NumPy dtype The dtype of the conversion factor Returns ------- conversion_factor : float `old_units / new_units` offset : float or None Offset between the old unit and new unit. """

    if old_units.dimensions != new_units.dimensions:
        raise UnitConversionError(
            old_units, old_units.dimensions, new_units, new_units.dimensions
        )
    ratio = old_units.base_value / new_units.base_value
    if old_units.base_offset == 0 and new_units.base_offset == 0:
        return (ratio, None)
    else:
        # the dimensions are the same, so both are temperatures, where
        # it's legal to convert units so no need to do error checking
        return ratio, ratio * old_units.base_offset - new_units.base_offset