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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 extract_table_names(query):
 """ Extract table names from an SQL query. """

    # a good old fashioned regex. turns out this worked better than actually parsing the code
    tables_blocks = re.findall(r'(?:FROM|JOIN)\s+(\w+(?:\s*,\s*\w+)*)', query, re.IGNORECASE)
    tables = [tbl
              for block in tables_blocks
              for tbl in re.findall(r'\w+', block)]
    return set(tables)