altair configuration to make pretty charts

altair.py

# Make sure to get all of the methods:
from altair import *

# set up some color vars:
rv_orange="#f38c21"
rv_red="#D24435"
rv_blue="#0099FF"
rv_green="#00B37C"

rv_orange_dark="#AA5C09"
rv_red_dark="#7D251C"
rv_blue_dark="#004D80"
rv_green_dark="#004D36"

rv_black="#222222"
rv_dark_gray="#444444"
rv_medium_gray="#666666"
rv_light_gray="#888888"

Chart(chartData).mark_bar(color=rv_blue_dark).encode(
    x=X('COLUMN_FOR_X_VALUES:Q', # q means "quantitative"
        title="TITLE OF X AXIS",),
    y=Y('COLUMN_FOR_Y_VALUES:O', # o means "object", or string
        title=" ", # blank out the title name for the y axis if it's obvious
        sort=SortField(field="X_COLUMN", order="descending", op='max'))
).configure(
    axis=AxisConfig(tickLabelFontSize=14,
                    titleFontSize=19,
                    titleFont="serif",
                    titleFontWeight="400",
                    titleColor=rv_medium_gray,
                    tickColor=rv_light_gray,
                    tickLabelColor=rv_light_gray,
                    axisColor=rv_light_gray, 
                    axisWidth=1,
                    gridColor=rv_light_gray,
                    tickLabelFont='Lato'),
    scale=ScaleConfig(bandSize=25),
).configure_cell(width=450, height=400 )