Ping '__ping_check_timestamp' attributes is turned to '_Pool__ping_check_timestamp' #16

$ python -V
Python 3.6.8

Debug Log

(Pdb)

/usr/local/lib/python3.6/site-packages/pymysqlpool/pool.py(177)__get_safe_conn()
-> if not hasattr(c, '__ping_check_timestamp'):
(Pdb) old_attributes = set(vars(c).keys())
/usr/local/lib/python3.6/site-packages/pymysqlpool/pool.py(178)__get_safe_conn()
-> c.__ping_check_timestamp = now
(Pdb) n
/usr/local/lib/python3.6/site-packages/pymysqlpool/pool.py(179)__get_safe_conn()
-> try:
(Pdb) cur_attributes = set(vars(c).keys())
(Pdb) old_attributes
{'encoding', 'host_info', 'unix_socket', '_rfile', '_connect_attrs', 'cursorclass', 'server_capabilities', 'server_public_key', 'db', '_closed', 'client_flag', '_write_timeout', 'encoders', 'init_command', 'server_charset', 'server_status', 'password', 'host', '_result', 'port', 'ssl', '_affected_rows', 'sql_mode', 'autocommit_mode', 'user', 'use_unicode', 'server_language', 'server_thread_id', '_auth_plugin_map', '_next_seq_id', '_read_timeout', 'protocol_version', 'bind_address', 'salt', 'max_allowed_packet', '_local_infile', 'server_version', 'connect_timeout', 'charset', '_sock', '_auth_plugin_name', '_binary_prefix', 'decoders'}
(Pdb) cur_attributes
{'encoding', 'host_info', '_Pool__ping_check_timestamp', 'unix_socket', '_rfile', '_connect_attrs', 'cursorclass', 'server_capabilities', 'server_public_key', 'db', '_closed', 'client_flag', '_write_timeout', 'encoders', 'init_command', 'server_charset', 'server_status', 'password', 'host', '_result', 'port', 'ssl', '_affected_rows', 'sql_mode', 'autocommit_mode', 'user', 'use_unicode', 'server_language', 'server_thread_id', '_auth_plugin_map', '_next_seq_id', '_read_timeout', 'protocol_version', 'bind_address', 'salt', 'max_allowed_packet', '_local_infile', 'server_version', 'connect_timeout', 'charset', '_sock', '_auth_plugin_name', '_binary_prefix', 'decoders'}
(Pdb) cur_attributes - old_attributes
{'_Pool__ping_check_timestamp'}

because of this, the Ping Check fails, This needs to be fixed?