human
Solve the following python programming problem given the following code:
# %load test_unique_chars.py
from nose.tools import assert_equal

class TestUniqueChars(object):

    def test_unique_chars(self, func):
        assert_equal(func(''), True)
        assert_equal(func('foo'), False)
        assert_equal(func('bar'), True)
        print('Success: test_unique_chars')

def main():
    test = TestUniqueChars()
    test.test_unique_chars(unique_chars)
    try:
        test.test_unique_chars(unique_chars_hash)
        test.test_unique_chars(unique_chars_inplace)
    except NameError:
        # Alternate solutions are only defined
        # in the solutions file
        pass

if __name__ == '__main__':
    main()
Given the above code, generate some markdown instructions for it.
assistant
#Here is the Python code you requested.

Unit Test
The following unit test is expected to fail until you solve the challenge.