Cohesion does not produce the same results with debug on and off

[mschwager]

For example:

$ cat example.py 
class ExampleClass1(object):
    class_variable1 = 5
    class_variable2 = 6

    def func1(self):
        self.instance_variable = 6

        def inner_func(b):
            return b + 5

        local_variable = self.class_variable1

        return local_variable

    def func2(self):
        print(self.class_variable2)

    @staticmethod
    def func3(variable):
        return variable + 7

class ExampleClass2(object):
    def func1(self):
        self.instance_variable1 = 7

Without the --debug flag:

$ PYTHONPATH=lib/ python -m cohesion -f example.py 
File: example.py
  Class: ExampleClass2 (22:0)
    Function: func1 1/1 100.00%
    Total: 100.00%
  Class: ExampleClass1 (1:0)
    Function: func3 staticmethod
    Function: func2 1/3 33.33%
    Function: func1 2/3 66.67%
    Total: 33.33%

With the --debug flag:

$ PYTHONPATH=lib/ python -m cohesion --debug -f example.py 
{
    "ExampleClass2": {
        "cohesion": null,
        "variables": [
            "instance_variable1"
        ],
        "lineno": 22,
        "col_offset": 0,
        "functions": {
            "func1": {
                "classmethod": false,
                "variables": [
                    "instance_variable1"
                ],
                "bounded": true,
                "staticmethod": false
            }
        }
    },
    "ExampleClass1": {
        "cohesion": null,
        "variables": [
            "class_variable2",
            "class_variable1",
            "instance_variable"
        ],
        "lineno": 1,
        "col_offset": 0,
        "functions": {
            "func3": {
                "classmethod": false,
                "variables": [],
                "bounded": false,
                "staticmethod": true
            },
            "func2": {
                "classmethod": false,
                "variables": [
                    "class_variable2"
                ],
                "bounded": true,
                "staticmethod": false
            },
            "func1": {
                "classmethod": false,
                "variables": [
                    "class_variable1",
                    "instance_variable"
                ],
                "bounded": true,
                "staticmethod": false
            }
        }
    }
}

Notice the cohesion value is null with debugging turned on. It looks like this value is calculated differently depending on if debugging is turned on. We should remedy this.