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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 namedb_get_names_with_value_hash( cur, value_hash, block_number ):
 """ Get the names with the given value hash. Only includes current, non-revoked names. Return None if there are no names. """


    unexpired_query, unexpired_args = namedb_select_where_unexpired_names( block_number )
    select_query = "SELECT name FROM name_records JOIN namespaces ON name_records.namespace_id = namespaces.namespace_id " + \
                   "WHERE value_hash = ? AND revoked = 0 AND " + unexpired_query + ";"

    args = (value_hash,) + unexpired_args
    name_rows = namedb_query_execute( cur, select_query, args )
    names = []

    for name_row in name_rows:
        names.append( name_row['name'] )

    if len(names) == 0:
        return None
    else:
        return names