Thanks @JK_NO for making me aware of these possibilities!

Do you happen to know how to open a protected project (existing) with Python? I tried to adapt the C# snippet in the Openness System Manual section 5.3.1 Opening a project / Opening a UMAC protected project with the additional parameter to the Open function by naively defining a function MyUmacDelegate and passing it to Open, but as this parameter has to be of type UmacDelegate this gives me

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Split from Openness with Python.

Now I found a way - instantiate an UmacDelegate with my function as argument; e. g.:

import Siemens.Engineering as SE

def MyUmacDelegate(umacCredentials):

    ss = System.Security.SecureString()

    for ch in sys.argv[3]: ss.AppendChar(ch)

    umacCredentials.Type = SE.UmacUserType.Project

    umacCredentials.Name = sys.argv[2]

    umacCredentials.SetPassword(ss)

project = mytia.Projects.Open(FileInfo(Path.GetFullPath(path)),
                              SE.UmacDelegate(MyUmacDelegate))

Did You tried to change the AuthenticationTypeProvider? I tried to do it in your (just a little personalized) code as shown further:

import Siemens.Engineering as tia  # noqa
import System  # noqa

def MyUmacDelegate(umacCredentials):

umacCredentials.AuthenticationTypeProvider = tia.AuthenticationTypeProvider.Interactive
print(type(umacCredentials.AuthenticationTypeProvider))
umacCredentials.Type = tia.UmacUserType.Project

try:

mytia.Projects.Open(FileInfo(path + file_proj), tia.UmacDelegate(MyUmacDelegate))

except Exception as ex:

template = "An exception of type {0} occurred. Arguments:\n{1!r}"
message = template.format(type(ex).__name__, ex.args)
if "The project is protected." in message:

print("Project protected. Either login or authentication is failed with provided credentials.")

else:

raise