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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 simple_transpile_modname_source_target( self, spec, modname, source, target):
 """ The original simple transpile method called by compile_transpile on each target. """


        opener = self.opener
        bd_target = self._generate_transpile_target(spec, target)
        logger.info('Transpiling %s to %s', source, bd_target)
        with opener(source, 'r') as reader, opener(bd_target, 'w') as _writer:
            writer = SourceWriter(_writer)
            self.transpiler(spec, reader, writer)
            if writer.mappings and spec.get(GENERATE_SOURCE_MAP):
                source_map_path = bd_target + '.map'
                with open(source_map_path, 'w') as sm_fd:
                    self.dump(encode_sourcemap(
                        filename=bd_target,
                        mappings=writer.mappings,
                        sources=[source],
                    ), sm_fd)

                # just use basename
                source_map_url = basename(source_map_path)
                _writer.write('\n//# sourceMappingURL=')
                _writer.write(source_map_url)
                _writer.write('\n')