code: def get_account_tokens(address, hostport=None, proxy=None):
      
      assert proxy or hostport, 'Need proxy or hostport'
      if proxy is None:
          proxy = connect_hostport(hostport)
  
      tokens_schema = {
          'type': 'object',
          'properties': {
              'token_types': {
                  'type': 'array',
                  'pattern': '^(.+){1,19}',
              },
          },
          'required': [
              'token_types',
          ]
      }
  
      schema = json_response_schema(tokens_schema)
  
      try:
          resp = proxy.get_account_tokens(address)
          resp = json_validate(schema, resp)
          if json_is_error(resp):
              return resp
  
      except ValidationError as ve:
          if BLOCKSTACK_DEBUG:
              log.exception(ve)
  
          resp = {'error': 'Server response did not match expected schema.  You are likely communicating with an out-of-date Blockstack node.', 'http_status': 502}
          return resp
  
      except socket.timeout:
          log.error("Connection timed out")
          resp = {'error': 'Connection to remote host timed out.', 'http_status': 503}
          return resp
  
      except socket.error as se:
          log.error("Connection error {}".format(se.errno))
          resp = {'error': 'Connection to remote host failed.', 'http_status': 502}
          return resp
  
      except AssertionError as ae:
          if BLOCKSTACK_DEBUG:
              log.exception(ae)
  
          resp = json_traceback(resp.get('error'))
          return resp
  
      except Exception as ee:
          if BLOCKSTACK_DEBUG:
              log.exception(ee)
  
          log.error("Caught exception while connecting to Blockstack node: {}".format(ee))
          resp = {'error': 'Failed to contact Blockstack node.  Try again with `--debug`.', 'http_status': 500}
          return resp
  
      resp['token_types'].sort()
      return resp['token_types']
docs: Get the types of tokens that an address owns
      Returns a list of token types