export {"symbol1", "symbol2", ...}
A package can contain the code for many functions, only some of which should be made visible to the user. The function export allows one to specify which symbols are to be made visible. For an example see an example of a package.
No single-letter symbol should be exported, since such symbols are reserved as variables for the user.
Use exportMutable to export symbols whose values the user is permitted to modify.
Use importFrom to import private symbols of a package.
The object export is a method function with a single argument.