coordinate = current_obj.data.vertices[vert].co
print("coordinate = ", coordinate.pop(2))
coordinate is a Vector and pop() removes an item from a list. You may want to alter a Vector value but it makes no sense to remove an item from a vector.
Blender offers several ways to access the data in a Vector -
# like an array
coordinate.[0]
# most will contain 3 items but 4d Vectors are used in some situations.
len(coordinate)
# get a specific item
coordinate.y
# get a combination of elements - many variations available - xyz zyx yzx ....
coordinate.xyz
# each of these can be returned as a tuple instead of a vector
coordinate.to_tuple()
coordinate.xyz.to_tuple()