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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 build_package_data(self):
 """Copy data files into build directory"""

        for package, src_dir, build_dir, filenames in self.data_files:
            for filename in filenames:
                target = os.path.join(build_dir, filename)
                self.mkpath(os.path.dirname(target))
                srcfile = os.path.join(src_dir, filename)
                outf, copied = self.copy_file(srcfile, target)
                srcfile = os.path.abspath(srcfile)
                if (copied and
                        srcfile in self.distribution.convert_2to3_doctests):
                    self.__doctests_2to3.append(outf)