Shell tests in http mode fail on CentOS 6

Error MessageAssertionError: Cmd ['--ssl', '-q', 'select 1 + 2'] was expected to succeed: Starting Impala Shell without Kerberos authentication SSL is enabled. Impala server certificates will NOT be verified (set --ca_cert to change) Warning: --connect_timeout_ms is currently ignored with HTTP transport. Error connecting: AttributeError, 'module' object has no attribute 'create_default_context' Not connected to Impala, could not execute queries.Stacktracecustom_cluster/test_client_ssl.py:90: in test_ssl
    self._validate_positive_cases(vector, "%s/server-cert.pem" % self.CERT_DIR)
custom_cluster/test_client_ssl.py:235: in _validate_positive_cases
    result = run_impala_shell_cmd(vector, shell_options, wait_until_connected=False)
shell/util.py:113: in run_impala_shell_cmd
    result.stderr)
E   AssertionError: Cmd ['--ssl', '-q', 'select 1 + 2'] was expected to succeed: Starting Impala Shell without Kerberos authentication
E   SSL is enabled. Impala server certificates will NOT be verified (set --ca_cert to change)
E   Warning: --connect_timeout_ms is currently ignored with HTTP transport.
E   Error connecting: AttributeError, 'module' object has no attribute 'create_default_context'
E   Not connected to Impala, could not execute queries.

[centos6 ~]# python
Python 2.6.6 (r266:84292, Jul 10 2013, 22:48:45) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 
>>> import ssl;
>>> ctx = ssl.create_default_context(Purpose.CLIENT_AUTH)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'create_default_context'

[centos 7.3 ~]# python
Python 2.7.5 (default, Jun 20 2019, 20:27:34) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-36)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl;
>>> ctx = ssl.create_default_context();
>>>