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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 must_exist(*components):
 """ Ensure path exists. Arguments: *components (str[]):
 Path components. Returns: str: File path. Raises: File404: If path does not exist. """

    _path = path(*components)
    if not exists(_path):
        raise File404(_path)
    return _path