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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 get_files_by_layer(self, layer_name, file_pattern='*'):
 """ returns a list of all files with the given filename pattern in the given PCC annotation layer """

        layer_path = os.path.join(self.path, layer_name)
        return list(dg.find_files(layer_path, file_pattern))