a valid #GParamSpec
source #GValue
destination #GValue of correct type for pspec
true requires dest_value to conform to pspec without modifications
true if transformation and validation were successful, false otherwise and dest_value is left untouched.
Transforms src_value into dest_value if possible, and then validates dest_value, in order for it to conform to pspec. If strict_validation is true this function will only succeed if the transformed dest_value complied to pspec without modifications.
See also gobject.value.Value.typeTransformable, gobject.value.Value.transform and gobject.global.paramValueValidate.