def process_documentline(line, nanopubs_metadata):
    """Process SET DOCUMENT line in BEL script"""

    matches = re.match('SET DOCUMENT\s+(\w+)\s+=\s+"?(.*?)"?$', line)
    key = matches.group(1)
    val = matches.group(2)
    nanopubs_metadata[key] = val

    return nanopubs_metadata
Process SET DOCUMENT line in BEL script