To get the size of a matrix in Python, you need to call the `shape`

property of the matrix object.

For example, suppose you created a matrix object using NumPy as shown below:

```
from numpy import matrix
my_matrix = matrix([[1,2],[3,4], [5,6]])
```

To know the size of the matrix and get how many rows and columns it has, you need to access the `shape`

attribute of the object:

```
print(my_matrix.shape)
```

**Output:**

```
(3, 2)
```

The `shape`

attribute returns a tuple that shows the size of the matrix in N rows and N columns format.

In this example, the matrix has 3 rows and 2 columns. You can use this attribute for any matrix you have in your source code.