class_docstr: Namespace for datetime related expressions.
docstr: Return a timestamp in the given time unit.
  
  Parameters
  ----------
  time_unit : {'ns', 'us', 'ms'}
      Time unit.
  
  Examples
  --------
  >>> from datetime import date
  >>> df = (
  ...     pl.date_range(date(2001, 1, 1), date(2001, 1, 3), eager=True)
  ...     .alias("date")
  ...     .to_frame()
  ... )
  >>> df.with_columns(
  ...     pl.col("date").dt.timestamp().alias("timestamp_ns"),
  ...     pl.col("date").dt.timestamp("ms").alias("timestamp_ms"),
  ... )
  shape: (3, 3)
  ┌────────────┬─────────────────┬──────────────┐
  │ date       ┆ timestamp_ns    ┆ timestamp_ms │
  │ ---        ┆ ---             ┆ ---          │
  │ date       ┆ i64             ┆ i64          │
  ╞════════════╪═════════════════╪══════════════╡
  │ 2001-01-01 ┆ 978307200000000 ┆ 978307200000 │
  │ 2001-01-02 ┆ 978393600000000 ┆ 978393600000 │
  │ 2001-01-03 ┆ 978480000000000 ┆ 978480000000 │
  └────────────┴─────────────────┴──────────────┘
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code: def timestamp(self, time_unit: TimeUnit = "us") -> Expr:
      """
      Return a timestamp in the given time unit.
  
      Parameters
      ----------
      time_unit : {'ns', 'us', 'ms'}
          Time unit.
  
      Examples
      --------
      >>> from datetime import date
      >>> df = (
      ...     pl.date_range(date(2001, 1, 1), date(2001, 1, 3), eager=True)
      ...     .alias("date")
      ...     .to_frame()
      ... )
      >>> df.with_columns(
      ...     pl.col("date").dt.timestamp().alias("timestamp_ns"),
      ...     pl.col("date").dt.timestamp("ms").alias("timestamp_ms"),
      ... )
      shape: (3, 3)
      ┌────────────┬─────────────────┬──────────────┐
      │ date       ┆ timestamp_ns    ┆ timestamp_ms │
      │ ---        ┆ ---             ┆ ---          │
      │ date       ┆ i64             ┆ i64          │
      ╞════════════╪═════════════════╪══════════════╡
      │ 2001-01-01 ┆ 978307200000000 ┆ 978307200000 │
      │ 2001-01-02 ┆ 978393600000000 ┆ 978393600000 │
      │ 2001-01-03 ┆ 978480000000000 ┆ 978480000000 │
      └────────────┴─────────────────┴──────────────┘
  
      """
      return wrap_expr(self._pyexpr.dt_timestamp(time_unit))
  
imports: from __future__ import annotations
  import datetime
  from typing import TYPE_CHECKING
  import polars._reexport
  from polars import functions
  from polars.datatypes import DTYPE_TEMPORAL_UNITS, Date, Int32
  from polars.utils._parse_expr_input import parse_as_expression
  from polars.utils._wrap import wrap_expr
  from polars.utils.convert import _timedelta_to_pl_duration
  from polars.utils.deprecation import deprecate_renamed_function, deprecate_saturating, issue_deprecation_warning, rename_use_earliest_to_ambiguous
label_desc: Use image node_id 26 for calling the ExprDateTimeNameSpace obj's underlying member method code with example usage: obj.timestamp(time_unit) and returns: wrap_expr