diff --git a/b_asic/_preferences.py b/b_asic/_preferences.py
index 53857f98f27a4136d587daf85e96eba021b2728c..c9bb219cf4478d4e12a6774c54f2e4dda1509615 100644
--- a/b_asic/_preferences.py
+++ b/b_asic/_preferences.py
@@ -2,10 +2,10 @@ LATENCY_COLOR = (0, 185, 231)
 EXECUTION_TIME_COLOR = (255, 100, 66, 200)
 SIGNAL_COLOR = (0, 0, 0)
 
-SIGNAL_LINEWIDTH = 1.0
+SIGNAL_LINEWIDTH: float = 1.0
 
-OPERATION_GAP = 0.5
+OPERATION_GAP: float = 0.5
 
-SCHEDULE_OFFSET = 0.2
+SCHEDULE_OFFSET: float = 0.2
 
-SPLINE_OFFSET = 0.2
+SPLINE_OFFSET: float = 0.2
diff --git a/b_asic/save_load_structure.py b/b_asic/save_load_structure.py
index 74d531312112425011bcf5ad065ec81287ca53cb..2a65db0a77d47d4900a15783efeaaec2c4f83d3b 100644
--- a/b_asic/save_load_structure.py
+++ b/b_asic/save_load_structure.py
@@ -16,7 +16,7 @@ from b_asic.signal_flow_graph import SFG
 
 
 def sfg_to_python(
-    sfg: SFG, counter: int = 0, suffix: Optional[str] = None, schedule=False
+    sfg: SFG, counter: int = 0, suffix: Optional[str] = None, schedule: bool = False
 ) -> str:
     """
     Given an SFG structure try to serialize it for saving to a file.
diff --git a/b_asic/schedule.py b/b_asic/schedule.py
index b07d41d53492b4416e1dbc22809cf7c04f0e3543..6d25eac3643d3af7a2e5b00f7ad8123fe6a0b807 100644
--- a/b_asic/schedule.py
+++ b/b_asic/schedule.py
@@ -7,7 +7,7 @@ Contains the schedule class for scheduling operations in an SFG.
 import io
 import sys
 from collections import defaultdict
-from typing import Dict, List, Optional, Tuple, cast
+from typing import Dict, List, Optional, Sequence, Tuple, cast
 
 import matplotlib.pyplot as plt
 import numpy as np
@@ -720,8 +720,8 @@ class Schedule:
         line_cache = []
 
         def _draw_arrow(
-            start: List[float], end: List[float], name: str = "", laps: int = 0
-        ):
+            start: Sequence[float], end: Sequence[float], name: str = "", laps: int = 0
+        ) -> None:
             """Draw an arrow from *start* to *end*."""
             if end[0] < start[0] or laps > 0:  # Wrap around
                 if start not in line_cache:
@@ -802,7 +802,14 @@ class Schedule:
                 )
                 ax.add_patch(path_patch)
 
-        def _draw_offset_arrow(start, end, start_offset, end_offset, name="", laps=0):
+        def _draw_offset_arrow(
+            start: Sequence[float],
+            end: Sequence[float],
+            start_offset: Sequence[float],
+            end_offset: Sequence[float],
+            name: str = "",
+            laps: int = 0,
+        ) -> None:
             """Draw an arrow from *start* to *end*, but with an offset."""
             _draw_arrow(
                 [start[0] + start_offset[0], start[1] + start_offset[1]],