How to use the leather.Chart function in leather

def test_line(self):
        chart = leather.Chart()
        chart.add_lines(self.data1)
        chart.add_lines(self.data2)
        chart.add_lines(self.data3)

        output = six.StringIO()
        chart.to_svg(output)

def test_add_one(self):
        chart1 = leather.Chart()
        chart1.add_dots(self.data1)

        chart2 = leather.Chart()
        chart2.add_dots(self.data2)

        grid = leather.Grid()
        grid.add_one(chart1)
        grid.add_one(chart2)

        svg = self.render_chart(grid)

        self.assertElementCount(svg, '.axis', 4)
        self.assertElementCount(svg, '.series', 2)
        self.assertElementCount(svg, '.dots', 2)
        self.assertElementCount(svg, 'circle', 9)

def test_column(self):
        chart = leather.Chart()
        chart.add_columns(self.data1)
        chart.add_columns(self.data2)
        chart.add_columns(self.data3)

        output = six.StringIO()
        chart.to_svg(output)

def test_dot(self):
        chart = leather.Chart()
        chart.add_dots(self.data1)
        chart.add_dots(self.data2)
        chart.add_dots(self.data3)

        output = six.StringIO()
        chart.to_svg(output)

def test_to_svg_file_handle(self):
        chart1 = leather.Chart()
        chart1.add_dots(self.data1)

        chart2 = leather.Chart()
        chart2.add_dots(self.data2)

        grid = leather.Grid()
        grid.add_many([chart1, chart2, chart1])

        with open('.test.svg', 'w') as f:
            grid.to_svg(f)

        self.assertTrue(os.path.exists(TEST_SVG))

def test_multiple_series(self):
        chart = leather.Chart()
        chart.add_dots(self.data1)
        chart.add_dots(self.data2)

        svg = self.render_chart(chart)

        self.assertElementCount(svg, '.axis', 2)
        self.assertElementCount(svg, '.series', 2)
        self.assertElementCount(svg, '.dots', 2)
        self.assertElementCount(svg, 'circle', 9)

def test_scale_domain_warning(self):
        chart = leather.Chart()
        chart.add_x_scale(4, 7)
        chart.add_y_scale(0, 20)
        chart.add_dots(self.data1)

        with warnings.catch_warnings():
            warnings.simplefilter('error')

            with self.assertRaises(UserWarning):
                self.render_chart(chart)

def test_to_svg_file_name(self):
        chart = leather.Chart()
        chart.add_dots(self.data1)

        chart.to_svg('.test.svg')

        self.assertTrue(os.path.exists(TEST_SVG))

import random

import leather


dot_data = [(random.randint(0, 250), random.randint(0, 250)) for i in range(100)]

def colorizer(d):
    return 'rgb(%i, %i, %i)' % (d.x, d.y, 150)

chart = leather.Chart('Colorized dots')
chart.add_dots(dot_data, fill_color=colorizer)
chart.to_svg('examples/charts/colorized_dots.svg')

import leather
import math
import csv

chart = leather.Chart('Income vs. health')

with open('data.csv', 'r') as csvfile:
    reader = csv.DictReader(csvfile)
    data = list(reader)
    
    def size_dot_by_area(x, y, i):
        return math.sqrt(int(data[i]['population'])) / 1000

    dots = leather.Dots('rgba(0,0,0,0.5)', radius=size_dot_by_area)

    series = leather.Series(
        data,
        dots,
        x=lambda row, i: math.log(float(row['income'])),
        y=lambda row, i: float(row['health']))