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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 compile_sass(input_file, output_file):
 """ Compile a SASS source file. Minifies the output in release mode. """

    from .modules import sass

    if not isinstance(input_file, str):
        raise RuntimeError('SASS compiler takes only a single input file.')

    return {
        'dependencies_fn': sass.sass_dependencies,
        'compiler_fn': sass.sass_compile,
        'input': input_file,
        'output': output_file,
        'kwargs': {},
    }