Allow custom samplers to request discard penultimate sigma

comfy/samplers.py

@@ -652,6 +652,7 @@ def sampler_object(name):
 class KSampler:
     SCHEDULERS = SCHEDULER_NAMES
     SAMPLERS = SAMPLER_NAMES
+    DISCARD_PENULTIMATE_SIGMA_SAMPLERS = set(('dpm_2', 'dpm_2_ancestral', 'uni_pc', 'uni_pc_bh2'))
 
     def __init__(self, model, steps, device, sampler=None, scheduler=None, denoise=None, model_options={}):
         self.model = model
@@ -670,7 +671,7 @@ class KSampler:
         sigmas = None
 
         discard_penultimate_sigma = False
-        if self.sampler in ['dpm_2', 'dpm_2_ancestral', 'uni_pc', 'uni_pc_bh2']:
+        if self.sampler in self.DISCARD_PENULTIMATE_SIGMA_SAMPLERS:
             steps += 1
             discard_penultimate_sigma = True