$inst->files(module[,string[,dir[,...]]])
Returns list of filenames. Parameters are:
Required. The name of a module; returns a list of all filenames in the package. For a list of core files, use the special module name Perl.
Optional. Possible values are prog, man, or all to
return program files, manual files, or all files, respectively.
Optional. One or more directories. If specified, only filenames under the specified directories are returned.