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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 process_unset(line, annotations):
 """Process UNSET lines in BEL Script"""


    matches = re.match('UNSET\s+"?(.*?)"?\s*$', line)
    if matches:
        val = matches.group(1)
        if val == "ALL" or val == "STATEMENT_GROUP":
            annotations = {}
        elif re.match("{", val):
            vals = convert_csv_str_to_list(val)
            for val in vals:
                annotations.pop(val, None)
        else:
            annotations.pop(val, None)

    else:
        log.warn(f"Problem with UNSET line: {line}")

    return annotations