$ ansible all  -i /tmp/myhosts -m shell -a 'uname -a' -u user1 -k
SSH password:
host1.mycomp.com | FAILED! => {
    "changed": false,
    "module_stderr": "",
    "module_stdout": "  File "/home/user1/.ansible/tmp/ansible-tmp-1556597037.27-168849792658772/AnsiballZ_command.py", line 39rn    with open(module, 'wb') as f:rn            ^rnSyntaxError: invalid syntaxrn",
    "msg": "MODULE FAILUREnSee stdout/stderr for the exact error",
    "rc": 1
}

$ more /tmp/myhosts
[mybox]
host1.mycomp.com
[dev]
host1.mycomp.com
[allserver:children]
mybox
dev
[allserver:vars]
variable=somestring

$ ssh user1@host1.mycomp.com
(AD: corp.mmco.int) Password:
Last login: Tue Apr 30 00:03:57 2019 from 10.23.232.126
$ hostname
host1

ansible --version
2.7.1