How can I use gridspec?

Could anyone show me how to use gridspec?
```jl
fig = figure();
gs = fig.add_gridspec(2,2);
ax1 = fig.add_subplot(gs[0,0]); # this works
ax2 = fig.add_subplot(gs[1,0:1]); #This does not work
```
I get the following error:
```jl
ERROR: Python: TypeError: '<' not supported between instances of 'range' and 'int'
```