Returns true if this declaration is considered private
according to the Dart language specification.
Always returns false if this declaration
is a library.
Otherwise return false.
Returns true if this mirror reflects dynamic, a non-generic class or
typedef, or an instantiated generic class or typedef in the current
isolate. Otherwise, returns false.
Checks the assignability relationship, denoted by <=> in the language
specification. This is the type relationship tested on assignment in
checked mode.