diff --git a/src/neps/optimizers/multi_fidelity/mf_bo.py b/src/neps/optimizers/multi_fidelity/mf_bo.py
index 4c845e93..3cf191bd 100755
--- a/src/neps/optimizers/multi_fidelity/mf_bo.py
+++ b/src/neps/optimizers/multi_fidelity/mf_bo.py
@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 from copy import deepcopy
+
 import numpy as np
 import pandas as pd
 import torch
@@ -15,8 +16,8 @@
 
 
 class MFBOBase:
-    """ Designed to work with model-based search on SH-based multi-fidelity algorithms.
-    
+    """Designed to work with model-based search on SH-based multi-fidelity algorithms.
+
     Requires certain strict assumptions about fidelities and rung maps.
     """
 
@@ -182,7 +183,7 @@ def sample_new_config(
 
 
 class FreezeThawModel:
-    """ Designed to work with model search in unit step multi-fidelity algorithms."""
+    """Designed to work with model search in unit step multi-fidelity algorithms."""
 
     def __init__(
         self,
@@ -240,19 +241,24 @@ def _fit(self, train_x, train_y, train_lcs):
             raise ValueError(
                 f"Surrogate model {self.surrogate_model_name} not supported!"
             )
-            
+
     def _predict(self, test_x, test_lcs):
         if self.surrogate_model_name in ["gp", "gp_hierarchy"]:
-            self.surrogate_model.predict(test_x)
+            return self.surrogate_model.predict(test_x)
         elif self.surrogate_model_name in ["deep_gp", "pfn"]:
-            self.surrogate_model.predict(test_x, test_lcs)
+            return self.surrogate_model.predict(test_x, test_lcs)
         else:
             # check neps/optimizers/bayesian_optimization/models/__init__.py for options
             raise ValueError(
                 f"Surrogate model {self.surrogate_model_name} not supported!"
             )
 
-    def set_state(self, pipeline_space, surrogate_model_args, **kwargs):
+    def set_state(
+        self,
+        pipeline_space,
+        surrogate_model_args,
+        **kwargs,  # pylint: disable=unused-argument
+    ):
         self.pipeline_space = pipeline_space
         self.surrogate_model_args = (
             surrogate_model_args if surrogate_model_args is not None else {}
@@ -260,9 +266,9 @@ def set_state(self, pipeline_space, surrogate_model_args, **kwargs):
         # only to handle tabular spaces
         if self.pipeline_space.has_tabular:
             if self.surrogate_model_name in ["deep_gp", "pfn"]:
-                self.surrogate_model_args.update({
-                    "pipeline_space": self.pipeline_space.raw_tabular_space
-                })
+                self.surrogate_model_args.update(
+                    {"pipeline_space": self.pipeline_space.raw_tabular_space}
+                )
             # instantiate the surrogate model, again, with the new pipeline space
             self.surrogate_model = instance_from_map(
                 SurrogateModelMapping,
@@ -289,12 +295,13 @@ def update_model(self, train_x=None, train_y=None, pending_x=None, decay_t=None)
 
 class PFNSurrogate(FreezeThawModel):
     """Special class to deal with PFN surrogate model and freeze-thaw acquisition."""
+
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.train_x = None
         self.train_y = None
 
-    def _fit(self, *args):
+    def _fit(self, *args):  # pylint: disable=unused-argument
         assert self.surrogate_model_name == "pfn"
         self.preprocess_training_set()
         self.surrogate_model.fit(self.train_x, self.train_y)
@@ -310,7 +317,7 @@ def preprocess_training_set(self):
             _configs = map_real_hyperparameters_from_tabular_ids(
                 pd.Series(_configs, index=_idxs), self.pipeline_space
             ).values
-        
+
         device = self.surrogate_model.device
         # TODO: fix or make consistent with `tokenize``
         configs, idxs, performances = self.observed_configs.get_tokenized_data(
@@ -326,9 +333,9 @@ def preprocess_test_set(self, test_x):
 
         new_idxs = np.arange(_len, len(test_x))
         base_fidelity = np.array([1] * len(new_idxs))
-        new_token_ids = np.hstack((
-            new_idxs.T.reshape(-1, 1), base_fidelity.T.reshape(-1, 1)
-        ))
+        new_token_ids = np.hstack(
+            (new_idxs.T.reshape(-1, 1), base_fidelity.T.reshape(-1, 1))
+        )
         # the following operation takes each element in the array and stacks it vertically
         # in this case, should convert a (n,) array to (n, 2) by flattening the elements
         existing_token_ids = np.vstack(self.observed_configs.token_ids).astype(int)