Hey @ElBrogrammer  I am working on test_nnz right now 
The code looks like this 
```python
def test_nnz(self):
        """What is your NNZ?"""
        for m in self.nulls:
            self.assertEqual(m.nnz, 0)

        self.assertEqual(self.empty.nnz, 0)
        self.assertEqual(self.single_ele.nnz, 1)
        self.assertEqual(self.mat1.nnz, 4)
        self.assertEqual(self.explicit_zeros.nnz, 4)
```
The table.nnz codes is here 
```python
@property
    def nnz(self):
        return self._data.nnz
```
The problem is that data is a numpy.ndarray  does not have an attraibute nnz
So i get the error
AttributeError: 'numpy.ndarray' object has no attribute 'nnz'  
Any idea what is going on here?