Grouped DataFrame Facets

from dataframe import Column, DataFrame, Series
from dataviz import save_facets, scatter_facets


def main() raises:
    var region: List[String] = [
        "South",
        "North",
        "South",
        "East",
        "North",
        "East",
    ]
    var product: List[String] = [
        "Product B",
        "Product A",
        "Product A",
        "Product B",
        "Product A",
        "Product A",
    ]
    var spend: List[Float64] = [8.0, 6.0, 11.0, 9.0, 13.0, 15.0]
    var revenue: List[Float64] = [12.0, 10.0, 16.0, 13.0, 20.0, 22.0]
    var campaigns = DataFrame(
        [
            Series("region", Column[String](region.copy())),
            Series("product", Column[String](product.copy())),
            Series("spend", Column[Float64](spend.copy())),
            Series("revenue", Column[Float64](revenue.copy())),
        ]
    )
    var panels = scatter_facets(
        campaigns,
        x="spend",
        y="revenue",
        facet="region",
        color="product",
        facet_order=["North", "South", "East"],
        color_order=["Product A", "Product B"],
        width=320,
        height=260,
    )
    save_facets(
        panels,
        2,
        "docs/src/examples/out_dataframe_grouped_facets.svg",
        shared_y_scale=True,
    )