Solution tests fails

[simendsjo]

$ ./run-tests.sh
................................F
======================================================================
FAIL: TEST 2.6: To be able to do anything useful, we need some basic math
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/nix/store/8z65fg9wa4vxi8sa4v55yyx00yj2wcrb-python3.6-nose-1.3.7/lib/python3.6/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/simendsjo/bekk/fagdag-feb-2019/diy-lang/tests/test_2_evaluating_simple_expressions.py", line 87, in test_basic_math_operators
    assert_equals(3, evaluate(["/", 7, 2], Environment()))
AssertionError: 3 != 3.5

----------------------------------------------------------------------
Ran 33 tests in 0.004s

FAILED (failures=1)

[kvalle]

Worked in Python 2, but not Python 3. Fixed now! :)