Change class checks to using isinstance

Author: gmingas

pymc3/sampling.py

@@ -903,7 +903,7 @@ def _iter_sample(
     try:
         step.tune = bool(tune)
         if hasattr(step, 'reset_tuning'):
-            if step.__class__.__name__ == 'CompoundStep':
+            if isinstance(step, CompoundStep):
                 if hasattr(step.methods[0], 'is_mlda_base'):
                     if not step.methods[0].is_mlda_base:
                         step.reset_tuning()

pymc3/step_methods/metropolis.py

@@ -21,6 +21,7 @@
 
 from ..distributions import draw_values
 from .arraystep import ArrayStepShared, PopulationArrayStepShared, ArrayStep, metrop_select, Competence
+from .compound import CompoundStep
 import pymc3 as pm
 from pymc3.theanof import floatX
 
@@ -1145,10 +1146,10 @@ def astep(self, q0):
 
         # Capture latest base chain scaling stats from next step method
         self.base_scaling_stats = {}
-        if self.next_step_method.__class__.__name__ == "CompoundStep":
+        if isinstance(self.next_step_method, CompoundStep):
             for method in self.next_step_method.methods:
                 self.base_scaling_stats["base_scaling_" + method.vars[0].name] = method.scaling
-        elif self.next_step_method.__class__.__name__ == "Metropolis":
+        elif isinstance(self.next_step_method, Metropolis):
             self.base_scaling_stats["base_scaling"] = self.next_step_method.scaling
         else:
             # next method is MLDA