The del statement
Delete names from a namespace, or attributes, members, or slices from an object.
del target list
Deletion is recursively defined very similar to the way assignment is defined. Rather that spelling it out in full details, here are some hints:
Deletion of a target list recursively deletes each target, from left to right.
Deletion of a name removes the binding of that name from the local or global namespace, depending on whether the name occurs in a global statement in the same code block. If the name is unbound, a NameError exception will be raised.
It is illegal to delete a name from the local namespace if it occurs as a free variable in a nested block.
Deletion of attribute references, subscriptions and slicings is passed to the primary object involved; deletion of a slicing is in general equivalent to assignment of an empty slice of the right type (but even this is determined by the sliced object).