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