diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 1a57593b..f3ac7830 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/psf/black
-    rev: 22.1.0
+    rev: 22.6.0
     hooks:
       - id: black
         files: 'mbrl'
@@ -13,11 +13,11 @@ repos:
         files: 'mbrl'
 
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.931
+    rev: v0.971
     hooks:
       - id: mypy
         files: 'mbrl'
-        additional_dependencies: [torch, tokenize-rt==3.2.0, types-PyYAML, types-termcolor]
+        additional_dependencies: [numpy, torch, tokenize-rt==3.2.0, types-PyYAML, types-termcolor]
         args: [--no-strict-optional, --ignore-missing-imports]
         exclude: setup.py
 
diff --git a/mbrl/util/common.py b/mbrl/util/common.py
index 98c7013b..18689b23 100644
--- a/mbrl/util/common.py
+++ b/mbrl/util/common.py
@@ -313,7 +313,7 @@ def get_sequence_buffer_iterator(
     if use_simple_sampler:
         train_iterator: _SequenceIterType = SequenceTransitionSampler(
             transitions,
-            train_trajectories,
+            train_trajectories,  # type:ignore
             batch_size,
             sequence_length,
             max_batches_per_loop_train,
@@ -322,7 +322,7 @@ def get_sequence_buffer_iterator(
     else:
         train_iterator = SequenceTransitionIterator(
             transitions,
-            train_trajectories,
+            train_trajectories,  # type: ignore
             batch_size,
             sequence_length,
             ensemble_size,
@@ -337,7 +337,7 @@ def get_sequence_buffer_iterator(
         if use_simple_sampler:
             val_iterator = SequenceTransitionSampler(
                 transitions,
-                val_trajectories,
+                val_trajectories,  # type: ignore
                 batch_size,
                 sequence_length,
                 max_batches_per_loop_val,
@@ -346,7 +346,7 @@ def get_sequence_buffer_iterator(
         else:
             val_iterator = SequenceTransitionIterator(
                 transitions,
-                val_trajectories,
+                val_trajectories,  # type: ignore
                 batch_size,
                 sequence_length,
                 1,
diff --git a/mbrl/util/replay_buffer.py b/mbrl/util/replay_buffer.py
index 32c2d2bb..dd5c46de 100644
--- a/mbrl/util/replay_buffer.py
+++ b/mbrl/util/replay_buffer.py
@@ -233,7 +233,7 @@ class SequenceTransitionIterator(BootstrapIterator):
     def __init__(
         self,
         transitions: TransitionBatch,
-        trajectory_indices: List[Tuple[int, int]],
+        trajectory_indices: Sequence[Tuple[int, int]],
         batch_size: int,
         sequence_length: int,
         ensemble_size: int,
@@ -266,7 +266,7 @@ def __init__(
 
     @staticmethod
     def _get_indices_valid_starts(
-        trajectory_indices: List[Tuple[int, int]],
+        trajectory_indices: Sequence[Tuple[int, int]],
         sequence_length: int,
     ) -> np.ndarray:
         # This is memory and time inefficient but it's only done once when creating the
@@ -332,7 +332,7 @@ class SequenceTransitionSampler(TransitionIterator):
     def __init__(
         self,
         transitions: TransitionBatch,
-        trajectory_indices: List[Tuple[int, int]],
+        trajectory_indices: Sequence[Tuple[int, int]],
         batch_size: int,
         sequence_length: int,
         batches_per_loop: int,
@@ -361,7 +361,7 @@ def __init__(
 
     @staticmethod
     def _get_indices_valid_starts(
-        trajectory_indices: List[Tuple[int, int]],
+        trajectory_indices: Sequence[Tuple[int, int]],
         sequence_length: int,
     ) -> np.ndarray:
         # This is memory and time inefficient but it's only done once when creating the
@@ -618,7 +618,7 @@ def sample_trajectory(self) -> Optional[TransitionBatch]:
         )
         return self._batch_from_indices(indices)
 
-    def _batch_from_indices(self, indices: Sized) -> TransitionBatch:
+    def _batch_from_indices(self, indices) -> TransitionBatch:
         obs = self.obs[indices]
         next_obs = self.next_obs[indices]
         action = self.action[indices]
diff --git a/setup.cfg b/setup.cfg
index 0704346f..49ae768c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -11,7 +11,7 @@ exclude =
     mbrl/third_party/*
 
 [mypy]
-python_version = 3.7
+python_version = 3.9
 ignore_missing_imports = True
 show_error_codes = True
 strict_optional = False