code: def dump_hash_prefix_values(self):
          
          q = '''SELECT distinct value from hash_prefix'''
          output = []
          with self.get_cursor() as dbc:
              dbc.execute(q)
              output = [bytes(r[0]) for r in dbc.fetchall()]
          return output
docs: Export all hash prefix values.
  
          Returns a list of known hash prefix values