def _normalize_metadata(metadata):
metadata = str(metadata)<EOL>metadata = metadata.lower()<EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', r'<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT:U+0020>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata)  <EOL>metadata = re.sub(r'<STR_LIT>', '<STR_LIT>', metadata, re.I)  <EOL>return metadata<EOL>
Normalize metadata to improve match accuracy.