def METHOD_NAME(self):
    '''
        Test the is_mbi_format_valid(mbi) function.
    '''
    # Build type_C_set: C – Numeric 1 thru 9
    type_C_set = set()
    for c in range(1, 10):
        type_C_set.add(str(c))
    # Build type_N_set: N – Numeric 0 thru 9
    type_N_set = set()
    for c in range(0, 10):
        type_N_set.add(str(c))
    # Build type_A_set: A – Alphabetic Character (A...Z); Excluding (S, L, O, I, B, Z)
    exclude_chars_set = {'S', 'L', 'O', 'I', 'B', 'Z'}
    type_A_set = set(ascii_uppercase).difference(exclude_chars_set)
    # Build type_A_pos2_set: A – Alphabetic Character (A...Z); Excluding (L, O, I, B, Z)
    #     In position 2, the "S" denotes a synthetic MBI.
    type_A_pos2_set = type_A_set | {"S"}
    # Build type_AN_set: AN – Either A or N
    type_AN_set = type_A_set | type_N_set
    # Base valid MBI
    base_valid_mbi = "4S10A00AA00"
    # 1. Test empty
    mbi = ""
    expected_return_value = [False, "Invalid length = 0"]
    # Assert validation return matches expected values.
    self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 2. Test size > 11
    mbi = "4S10A00AA00Z"
    expected_return_value = [False, "Invalid length = 12"]
    # Assert validation return matches expected values.
    self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 3. Test base_valid MBI
    mbi = base_valid_mbi
    expected_return_value = [True, "Valid"]
    # Assert validation return matches expected values.
    self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 4. Test type_C MBI position
    test_position = 0
    #     Valid tests:
    expected_return_value = [True, "Valid"]
    for c in type_C_set:
        mbi = c + base_valid_mbi[1:12]
        # Assert validation return matches expected values.
        self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    #     Invalid tests using type_A_set:
    expected_return_value = [False, "Invalid char in pos = " + str(test_position)]
    for c in type_A_set | {'0'}:
        mbi = c + base_valid_mbi[1:12]
        # Assert validation return matches expected values.
        self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 5. Test type_N MBI in positions:
    test_positions = [3, 6, 9, 10]
    for test_position in test_positions:
        # Valid tests:
        expected_return_value = [True, "Valid"]
        for c in type_N_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
        # Invalid tests using type_A_set:
        expected_return_value = [False, "Invalid char in pos = " + str(test_position)]
        for c in type_A_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 6. Test type_A MBI in positions:
    test_positions = [4, 7, 8]
    for test_position in test_positions:
        # Valid tests:
        expected_return_value = [True, "Valid"]
        for c in type_A_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
        # Invalid tests using type_N_set and exclude_chars_set
        expected_return_value = [False, "Invalid char in pos = " + str(test_position)]
        for c in type_N_set | exclude_chars_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 7. Test type_A_pos2 MBI in positions:
    test_position = 1
    # Valid tests:
    expected_return_value = [True, "Valid"]
    for c in type_A_pos2_set:
        mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
        # Assert validation return matches expected values.
        self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # Invalid tests using type_N_set and exclude_chars_set
    expected_return_value = [False, "Invalid char in pos = " + str(test_position)]
    for c in type_N_set | exclude_chars_set.difference({"S"}):
        mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
        # Assert validation return matches expected values.
        self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
    # 8. Test type_AN MBI in positions:
    test_positions = [2, 5]
    for test_position in test_positions:
        # Valid tests:
        expected_return_value = [True, "Valid"]
        for c in type_AN_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))
        # Invalid tests using exclude_chars_set
        expected_return_value = [False, "Invalid char in pos = " + str(test_position)]
        for c in exclude_chars_set:
            mbi = base_valid_mbi[0:test_position] + c + base_valid_mbi[test_position + 1:12]
            # Assert validation return matches expected values.
            self.assertTrue(self.check_is_mbi_format_valid(mbi, expected_return_value))