Merging PR_218 openai_rev package with new streamlit chat app

venv/lib/python3.9/site-packages/altair/examples/density_stack.py

@@ -0,0 +1,35 @@
+"""
+Stacked Density Estimates
+-------------------------
+To plot a stacked graph of estimates, use a shared ``extent`` and a fixed
+number of subdivision ``steps`` to ensure that the points for each area align
+well.  Density estimates of measurements for each iris flower feature are plot
+in a stacked method.  In addition, setting ``counts`` to true multiplies the
+densities by the number of data points in each group, preserving proportional
+differences.
+"""
+# category: area charts
+
+import altair as alt
+from vega_datasets import data
+
+source = data.iris()
+
+alt.Chart(source).transform_fold(
+    ['petalWidth', 
+     'petalLength', 
+     'sepalWidth', 
+     'sepalLength'], 
+    as_ = ['Measurement_type', 'value']
+).transform_density(
+    density='value', 
+    bandwidth=0.3, 
+    groupby=['Measurement_type'], 
+    extent= [0, 8], 
+    counts = True, 
+    steps=200
+).mark_area().encode(
+    alt.X('value:Q'), 
+    alt.Y('density:Q', stack='zero'),
+    alt.Color('Measurement_type:N')
+).properties(width=400, height=100)