Delete an option definition set by define.
This is not the same as setting the option to a null value.
The undefine method removes the option name from the list
of options for the specified format.
format = An image format name such as "ps" or "tiff".
key = A string that identifies the option.
Delete an option definition set by define. This is not the same as setting the option to a null value. The undefine method removes the option name from the list of options for the specified format. format = An image format name such as "ps" or "tiff". key = A string that identifies the option.