code: def _get_scale(
      df: pd.DataFrame, column_name: str | None
  ) -> alt.Scale:
      import altair as alt
  
      # Set the X and Y axes' scale to "utc" if they contain date values.
      # This causes time data to be displayed in UTC, rather the user's local
      # time zone. (By default, vega-lite displays time data in the browser's
      # local time zone, regardless of which time zone the data specifies:
      # https://vega.github.io/vega-lite/docs/timeunit.html#output).
      if _is_date_column(df, column_name):
          return alt.Scale(type="utc")
  
      return alt.Scale()
  
imports: from __future__ import annotations
  from contextlib import nullcontext
  from datetime import date
  from enum import Enum
  from typing import TYPE_CHECKING, Any, Collection, Dict, List, Sequence, Tuple, cast
  import pandas
  from pandas.api.types import infer_dtype, is_integer_dtype
  from typing_extensions import Literal
  import streamlit.elements.arrow_vega_lite
  from streamlit import type_util
  from streamlit.color_util import Color, is_color_like, is_color_tuple_like, is_hex_color_like, to_css_color
  from streamlit.elements.altair_utils import AddRowsMetadata
  from streamlit.elements.arrow import Data
  from streamlit.elements.utils import last_index_for_melted_dataframes
  from streamlit.errors import Error, StreamlitAPIException
  from streamlit.proto.ArrowVegaLiteChart_pb2 import ArrowVegaLiteChart
  from streamlit.runtime.metrics_util import gather_metrics
label_desc: Use image node_id 13 for calling a global function with example usage: _get_scale(df, column_name) and returns: alt, alt