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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 _find_file(self, path, silent=False):
 """ Gets the full path and extension, or None if a README file could not be found at the specified path. """

        for filename in DEFAULT_FILENAMES:
            full_path = os.path.join(path, filename) if path else filename
            if os.path.exists(full_path):
                return full_path

        # Return default filename if silent
        if silent:
            return os.path.join(path, DEFAULT_FILENAME)

        raise ReadmeNotFoundError(path)