old_contents: """
  Bar Chart with Highlighted Segment
  ----------------------------------
  This example shows a bar chart that highlights values beyond a threshold.
  """
  import altair as alt
  import pandas as pd
  from vega_datasets import data
  
  source = data.wheat()
  threshold = pd.DataFrame([{"threshold": 90}])
  
  bars = alt.Chart(source).mark_bar().encode(
      x="year:O",
      y="wheat:Q",
  )
  
  highlight = alt.Chart(source).mark_bar(color="#e45755").encode(
      x='year:O',
      y='baseline:Q',
      y2='wheat:Q'
  ).transform_filter(
      alt.datum.wheat > 90
  ).transform_calculate("baseline", "90")
  
  rule = alt.Chart(threshold).mark_rule().encode(
      y='threshold:Q'
  )
  
  (bars + highlight + rule).properties(width=600)
  
new_contents: """
  Bar Chart with Highlighted Segment
  ----------------------------------
  This example shows a bar chart that highlights values beyond a threshold.
  """
  # category: bar charts
  import altair as alt
  import pandas as pd
  from vega_datasets import data
  
  source = data.wheat()
  threshold = pd.DataFrame([{"threshold": 90}])
  
  bars = alt.Chart(source).mark_bar().encode(
      x="year:O",
      y="wheat:Q",
  )
  
  highlight = alt.Chart(source).mark_bar(color="#e45755").encode(
      x='year:O',
      y='baseline:Q',
      y2='wheat:Q'
  ).transform_filter(
      alt.datum.wheat > 90
  ).transform_calculate("baseline", "90")
  
  rule = alt.Chart(threshold).mark_rule().encode(
      y='threshold:Q'
  )
  
  (bars + highlight + rule).properties(width=600)
  
subject: Move bar chart with highlighted segment chart into the bar charts section