fix: replace mutable default argument in override_dist_dtype_device_args

[Mr-Neutr0n]

Summary

• Replace mutable default argument b={} with b=None in override_dist_dtype_device_args in both utils/models/cogvlm_model.py and utils/models/cogagent_model.py
• Initialize b to {} inside the function body when None is passed

Motivation

Using a mutable default argument (b={}) is a well-known Python anti-pattern (docs). The default dict is created once at function definition time and shared across all calls. If it is ever mutated, the mutation persists into subsequent calls, leading to subtle and hard-to-diagnose bugs.

Changes

utils/models/cogvlm_model.py (line 38):

# Before
def override_dist_dtype_device_args(args, b={}):

# After
def override_dist_dtype_device_args(args, b=None):
    if b is None:
        b = {}

utils/models/cogagent_model.py (line 39):
Same fix applied.

Test plan

• Verified the fix is syntactically correct
• No functional change when callers pass an explicit dict
• Callers relying on the default now get a fresh dict each time (correct behavior)