diff --git a/python-spec/src/somacore/coordinates.py b/python-spec/src/somacore/coordinates.py
index 6168050..cd18f9e 100644
--- a/python-spec/src/somacore/coordinates.py
+++ b/python-spec/src/somacore/coordinates.py
@@ -26,10 +26,10 @@ class Axis(metaclass=abc.ABCMeta):
     scale: Optional[np.float64] = None
 
 
-class CoordinateSpace(Sequence[Axis]):
+class CoordinateSpace(Sequence):
     """A coordinate system for spatial data."""
 
-    def __init__(self, axes: Sequence[Axis]):
+    def __init__(self, axes: typing.Sequence[Axis]):
         """TODO: Add docstring"""
         # TODO: Needs good, comprehensive error handling.
         if len(tuple(axes)) == 0: