The `del' statement
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del_stmt: "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 (which must exist)
from the local or global namespace, depending on whether the name
occurs in a `global' statement in the same code 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).