def test_1():
assert colors() == ['red', 'blue', 'yellow', 'chartreuse']
def test_2():
assert colors('black', 'blue', 'yellow',
'green') == ['black', 'blue', 'yellow', 'green']
def test_3():
assert colors('orange', link_color="purple") == [
'orange', 'blue', 'purple', 'chartreuse'
]
def test_4():
regular = ('red', 'blue')
links = {'link_color': 'chartreuse'}
assert colors(*regular, **links) == ('red', 'blue', 'chartreuse', None)
def test_2():
assert colors(link_color='red',
back_color='blue') == (None, 'blue', 'red', None)
def test_4():
regular = ('red', 'blue')
links = {'link_color': 'chartreuse'}
colors(*regular, **links) == ('red', 'blue', 'chartreuse', 'purple')
def test_3():
assert colors('purple', link_color='red',
back_color='blue') == ('purple', 'blue', 'red', None)
def test_2():
assert colors(link_color='red',
back_color='blue') == ('white', 'blue', 'red', 'purple')
def test_4():
assert colors(*regular, **links) == (('red', 'blue',), {'link_color': 'chartreuse'})
def test_3():
assert colors('purple', link_color='red', back_color='blue') == \
(('purple',), {'link_color':'red', 'back_color':'blue'})
def test_2():
assert colors(link_color='red', back_color='blue') == \
((), {'link_color':'red', 'back_color':'blue'})
def test_1():
assert colors('red', 'blue', 'yellow', 'chartreuse') == \
(('red', 'blue', 'yellow', 'chartreuse'), {})