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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_alias_file_path(alias_file_path):
 """ Make sure the alias file path is neither non-existant nor a directory Args: The alias file path to import aliases from. """

    if not os.path.exists(alias_file_path):
        raise CLIError(ALIAS_FILE_NOT_FOUND_ERROR)

    if os.path.isdir(alias_file_path):
        raise CLIError(ALIAS_FILE_DIR_ERROR.format(alias_file_path))