Make type hints more backward compatible.

Author: kyleaoman

velociraptor/__init__.py

@@ -30,19 +30,14 @@
 from velociraptor.catalogue.catalogue import VelociraptorCatalogue
 from velociraptor.__version__ import __version__
 
-try:
-    from types import EllipsisType  # python3.10+
-except ImportError:
-    from typing import Any as EllipsisType  # better choice for this?
 from typing import Union
-from numpy.typing import NDArray
 
 
 def load(
     filename: str,
     disregard_units: bool = False,
     registration_file_path: Union[str, None] = None,
-    mask: Union[EllipsisType, NDArray[bool], int] = Ellipsis
+    mask: slice = Ellipsis
 ) -> VelociraptorCatalogue:
     """
     Loads a velociraptor catalogue, producing a VelociraptorCatalogue

velociraptor/catalogue/catalogue.py

@@ -10,9 +10,6 @@
 import numpy as np
 
 from typing import Union, Callable, List, Dict
-from numpy.typing import NDArray
-# from types import EllipsisType  # requires python 3.10+
-import builtins  # use 'builtins.ellipsis' instead
 
 from velociraptor.units import VelociraptorUnits
 from velociraptor.catalogue.derived import DerivedQuantities
@@ -171,7 +168,7 @@ def generate_sub_catalogue(
     registration_function: Callable,
     units: VelociraptorUnits,
     field_metadata: List[VelociraptorFieldMetadata],
-    mask: Union['builtins.ellipsis', NDArray[bool], int] = Ellipsis
+    mask: slice = Ellipsis
 ):
     """
     Generates a sub-catalogue object with the correct properties set.
@@ -262,7 +259,7 @@ def __init__(
         filename: str,
         disregard_units: bool = False,
         extra_registration_functions: Union[None, Dict[str, Callable]] = None,
-        mask: Union['builtins.ellipsis', NDArray[bool], int] = Ellipsis,
+        mask: slice = Ellipsis,
     ):
         """
         Initialise the velociraptor catalogue with all of the available
@@ -290,7 +287,7 @@ def __init__(
             conform to the registration function API. This is an advanced
             feature.
 
-        mask: Union['builtins.ellipsis', NDArray[bool], int], optional
+        mask: slice, optional
             If a boolean array is provided, it is used to mask all catalogue
             arrays. If an int is provided, catalogue arrays are masked to the
             single corresponding element. Default: Ellipsis (``...``).