Add documentation of behaviour of get_item and compute for LazyExprs

Author: Luke Shaw

src/blosc2/lazyexpr.py

@@ -279,7 +279,8 @@ def compute(self, item: slice | list[slice] | None = None, **kwargs: Any) -> blo
         ----------
         item: slice, list of slices, optional
             If not None, only the chunks that intersect with the slices
-            in items will be evaluated.
+            in item will be evaluated. If provided, items of the operands to be used in computation.
+            Important to note that item is used to slice the operands PRIOR to computation.
 
         kwargs: Any, optional
             Keyword arguments that are supported by the :func:`empty` constructor.
@@ -328,7 +329,9 @@ def __getitem__(self, item: int | slice | Sequence[slice]) -> blosc2.NDArray:
         Parameters
         ----------
         item: int, slice or sequence of slices
-            The slice(s) to be retrieved. Note that step parameter is not yet honored.
+            If provided, items of the operands to be used in computation.
+            Important to note that item is used to slice the operands PRIOR to computation, not to retrieve specified
+            slices of the evaluated result.
 
         Returns
         -------
@@ -2689,21 +2692,6 @@ def sort(self, order: str | list[str] | None = None) -> blosc2.LazyArray:
         return lazy_expr
 
     def compute(self, item=None, **kwargs) -> blosc2.NDArray:
-        """
-        Compute the expression with the given item and kwargs.
-        Parameters
-        ----------
-        item: int, slice or sequence of slices, optional
-            The slice(s) of the operands to be used in computation. Note that step parameter is not honored yet.
-            Item is used to slice the operands PRIOR to computation.
-        kwargs
-
-        Returns:
-        blosc2.NDArray or numpy.ndarray
-        -------
-
-        """
-
         # When NumPy ufuncs are called, the user may add an `out` parameter to kwargs
         if "out" in kwargs:
             kwargs["_output"] = kwargs.pop("out")
@@ -2738,17 +2726,6 @@ def compute(self, item=None, **kwargs) -> blosc2.NDArray:
         return result
 
     def __getitem__(self, item):
-        """
-        Apply LazyExpr on a slice of the oeprands.
-        Parameters
-        ----------
-        item: int, slice or sequence of slices, optional
-            The slice(s) of the operands to be used in computation. Note that step parameter is not honored yet.
-            Item is used to slice the operands PRIOR to computation.
-        Returns:
-        numpy.ndarray
-        """
-
         kwargs = {"_getitem": True}
         return self.compute(item, **kwargs)