How to use the curtsies.fmtfuncs.on_blue function in curtsies

def __init__(self, width, height):
        self.width = width
        self.height = height
        n = 5
        self.player = Entity(on_blue(green(bold(u'5'))), width // 2, height // 2 - 2, speed=5)
        self.npcs = [Entity(on_blue(red(u'X')), i * width // (n * 2), j * height // (n * 2))
                     for i in range(1, 2*n, 2)
                     for j in range(1, 2*n, 2)]
        self.turn = 0

def test_ljust_rjust(self):
        """"""
        b = fmtstr(u'ab', 'blue', 'on_red', 'bold')
        g = fmtstr(u'cd', 'green', 'on_red', 'bold')
        s = b + g
        self.assertEqual(s.ljust(6), b + g + on_red('  '))
        self.assertEqual(s.rjust(6), on_red('  ') + b + g)

        # doesn't add empties to end
        self.assertEqual(s.ljust(4), b + g)
        self.assertEqual(s.rjust(4), b + g)

        # behavior if background different
        s = on_blue('a') + on_green('b')
        self.assertEqual(s.ljust(3), fmtstr('ab '))
        self.assertEqual(s.rjust(3), fmtstr(' ab'))
        s = blue(on_blue('a')) + green(on_green('b'))
        self.assertEqual(s.ljust(3), blue('a') + green('b') + fmtstr(' '))
        self.assertEqual(s.rjust(3), fmtstr(' ') + blue('a') + green('b'))

        #using fillchar
        self.assertEqual(s.ljust(3, '*'), fmtstr('ab*'))
        self.assertEqual(s.rjust(3, '*'), fmtstr('*ab'))

def test_multiple_bfs_splice(self):
        self.assertEqual(fmtstr('a') + blue('b'),
                         on_blue(' '*2).splice(fmtstr('a')+blue('b'), 0, 2))
        self.assertEqual(on_red('yo') + on_blue('   '),
                         on_blue(' '*5).splice(on_red('yo'), 0, 2))
        self.assertEqual(' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*6).splice(' ' + on_red('yo'), 0, 3))
        self.assertEqual(on_blue("hey") + ' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*9).splice(on_blue("hey") + ' ' + on_red('yo'), 0, 6))
        self.assertEqual(on_blue(' '*5) + on_blue("hey") + ' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*14).splice(on_blue("hey") + ' ' + on_red('yo'), 5, 11))

def test_bg(self):
        on_red('asdf')
        on_blue('asdf')
        self.assertTrue(True)

def test_multiple_bfs_splice(self):
        self.assertEqual(fmtstr('a') + blue('b'),
                         on_blue(' '*2).splice(fmtstr('a')+blue('b'), 0, 2))
        self.assertEqual(on_red('yo') + on_blue('   '),
                         on_blue(' '*5).splice(on_red('yo'), 0, 2))
        self.assertEqual(' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*6).splice(' ' + on_red('yo'), 0, 3))
        self.assertEqual(on_blue("hey") + ' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*9).splice(on_blue("hey") + ' ' + on_red('yo'), 0, 6))
        self.assertEqual(on_blue(' '*5) + on_blue("hey") + ' ' + on_red('yo') + on_blue('   '),
                         on_blue(' '*14).splice(on_blue("hey") + ' ' + on_red('yo'), 5, 11))

from __future__ import unicode_literals # convenient for Python 2
import random

from curtsies import FullscreenWindow, Input, FSArray
from curtsies.fmtfuncs import red, bold, green, on_blue, yellow

print(yellow('this prints normally, not to the alternate screen'))
with FullscreenWindow() as window:
    with Input() as input_generator:
        msg = red(on_blue(bold('Press escape to exit')))
        a = FSArray(window.height, window.width)
        a[0:1, 0:msg.width] = [msg]
        window.render_to_terminal(a)
        for c in input_generator:
            if c == '':
                break
            elif c == '':
                a = FSArray(window.height, window.width)
            else:
                s = repr(c)
                row = random.choice(range(window.height))
                column = random.choice(range(window.width-len(s)))
                color = random.choice([red, green, on_blue, yellow])
                a[row, column:column+len(s)] = [color(s)]
            window.render_to_terminal(a)