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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 validate_model_specification_file(file_path: str) -> str: """Ensures the provided file is a yaml file"""

    if not os.path.isfile(file_path):
        raise ConfigurationError('If you provide a model specification file, it must be a file. '
                                 f'You provided {file_path}')

    extension = file_path.split('.')[-1]
    if extension not in ['yaml', 'yml']:
        raise ConfigurationError(f'Model specification files must be in a yaml format. You provided {extension}')
    # Attempt to load
    yaml.full_load(file_path)
    return file_path