diff --git a/polars_xdt/functions.py b/polars_xdt/functions.py
index 3084b41..6caee50 100644
--- a/polars_xdt/functions.py
+++ b/polars_xdt/functions.py
@@ -23,7 +23,9 @@
 
 
 if parse_version(pl.__version__) < parse_version("0.20.16"):
-    from polars.utils.udfs import _get_shared_lib_location
+    from polars.utils.udfs import (  # type: ignore[import-not-found]
+        _get_shared_lib_location,
+    )
 
     lib: str | Path = _get_shared_lib_location(__file__)
 else:
diff --git a/polars_xdt/ranges.py b/polars_xdt/ranges.py
index 1a3d852..52168ad 100644
--- a/polars_xdt/ranges.py
+++ b/polars_xdt/ranges.py
@@ -10,7 +10,7 @@
 if TYPE_CHECKING:
     from datetime import date, datetime, timedelta
 
-    from polars.type_aliases import ClosedInterval, IntoExprColumn, TimeUnit
+    from polars.type_aliases import ClosedInterval, IntoExprColumn
 
 
 @overload
@@ -20,8 +20,6 @@ def date_range(
     interval: str | timedelta = "1d",
     *,
     closed: ClosedInterval = ...,
-    time_unit: TimeUnit | None = ...,
-    time_zone: str | None = ...,
     eager: Literal[False] = ...,
     weekend: Sequence[str] = ...,
     holidays: Sequence[date] | None = ...,
@@ -35,8 +33,6 @@ def date_range(
     interval: str | timedelta = "1d",
     *,
     closed: ClosedInterval = ...,
-    time_unit: TimeUnit | None = ...,
-    time_zone: str | None = ...,
     eager: Literal[True],
     weekend: Sequence[str] = ...,
     holidays: Sequence[date] | None = ...,
@@ -50,8 +46,6 @@ def date_range(
     interval: str | timedelta = "1d",
     *,
     closed: ClosedInterval = ...,
-    time_unit: TimeUnit | None = ...,
-    time_zone: str | None = ...,
     eager: bool = ...,
     weekend: Sequence[str] = ...,
     holidays: Sequence[date] | None = ...,
@@ -59,13 +53,11 @@ def date_range(
 
 
 def date_range(  # noqa: PLR0913
-    start: date | datetime | IntoExprColumn,
-    end: date | datetime | IntoExprColumn,
+    start: date | IntoExprColumn,
+    end: date | IntoExprColumn,
     interval: str | timedelta = "1bd",
     *,
     closed: ClosedInterval = "both",
-    time_unit: TimeUnit | None = None,
-    time_zone: str | None = None,
     eager: bool = False,
     weekend: Sequence[str] = ("Sat", "Sun"),
     holidays: Sequence[date] | None = None,
@@ -87,12 +79,6 @@ def date_range(  # noqa: PLR0913
         "Examples" section below).
     closed : {'both', 'left', 'right', 'none'}
         Define which sides of the range are closed (inclusive).
-    time_unit : {None, 'ns', 'us', 'ms'}
-        Time unit of the resulting ``Datetime`` data type.
-        Only takes effect if the output column is of type ``Datetime``.
-    time_zone
-        Time zone of the resulting ``Datetime`` data type.
-        Only takes effect if the output column is of type ``Datetime``.
     eager
         Evaluate immediately and return a ``Series``.
         If set to ``False`` (default), return an expression instead.
@@ -152,8 +138,6 @@ def date_range(  # noqa: PLR0913
         end,
         interval,
         closed=closed,
-        time_unit=time_unit,
-        time_zone=time_zone,
         eager=False,
     )
     expr = expr.filter(~expr.dt.date().is_in(holidays))
diff --git a/src/expressions.rs b/src/expressions.rs
index ab71e33..29d35f1 100644
--- a/src/expressions.rs
+++ b/src/expressions.rs
@@ -203,3 +203,25 @@ fn ewma_by_time(inputs: &[Series], kwargs: EwmTimeKwargs) -> PolarsResult<Series
         _ => polars_bail!(InvalidOperation: "First argument should be a date or datetime type."),
     }
 }
+
+#[polars_expr(output_type_func=same_output)]
+fn truncate(inputs: &[Series]) -> PolarsResult<Series> {
+    let ser = &inputs[0];
+    let ca = ser.datetime()?;
+    let tu = ca.time_unit();
+    let tz = ca.time_zone();
+    let ca = &ca.0;
+    let duration = 7200000000;
+    let out = ca
+        .apply_values(|t| {
+            let mut remainder = t % duration;
+            if remainder < 0 {
+                remainder += duration
+            }
+            t - remainder
+        })
+        .into_datetime(tu, tz.clone())
+        .into_series();
+
+    Ok(out)
+}