Please code in python: def drop$($self$,$ item: str$)->$ int: # $|$ None:

$"""$

Return the row$-$coordinate of where the landed when dropped into

this column.

Dropping refers to inserting the into this column so that the

Square with the largest row$-$coordinate that previously had a value of

None now has as its symbol.

See the assignment materials for a diagram.

Preconditions:

$-$ is$\_$column$($self$.$cells$)$

$-$ not self.is$\_$full$()$

$-$ item in $(\text{'}$X$\text{'},\text{'}$O$\text{'})$

$>>>$ l $=$ Line$([$Square$((0,0)),$ Square$((1,0)),$

$...$ Square$((2,0)),$ Square$((3,0))])$ # an empty column

$>>>$ row$\_$coord $=$ l$.$drop$(\text{'}$X$\text{'})$

$>>>$ row$\_$coord

$3$

# $>>>$ print$($l$[$row$\_$coord$])$

X

$"""$