import subprocess
COMMAND_LINE = 'powershell'
powershell = subprocess.Popen(COMMAND_LINE, shell=True,
                                   stdin=subprocess.PIPE,
                                   stderr=subprocess.STDOUT,
                                   stdout=subprocess.PIPE)
output = powershell.stdout.readline()
print output.rstrip()
powershell.stdin.write('$cred = Get-Credentialn')
powershell.stdin.write('Administratorn')
powershell.stdin.write('Password')
output = powershell.stdout.readline()
print output.rstrip()
out = powershell.communicate()[0]
print(out)

> PS /root> $cred = Get-Credential
>
> Windows PowerShell credential request Enter your credentials. User:
> Administrator Password for user Administrator: PS /root>
> PasswordPassword : The term 'Password' is not recognized as the name
> of a cmdlet, function, script file, or operable program. Check the
> spelling of the name, or if a path was included, verify that the path
> is correct and try again. At line:1 char:1
> + Password
> + ~~~~~~~~
>     + CategoryInfo          : ObjectNotFound: (Password:String) [], CommandNot    FoundException
>     + FullyQualifiedErrorId : CommandNotFoundException