Each method call has a signature for incoming and outgoing parameters Examples: *ii*: two 32bit signed integers *tn*: a 64bit unsigned integer, and a 16bit signed integer *ssiib*: two strings, two integers and a byte *ad*: an array of doubles (each array has one type following to determine the child's type) *a{sv}*: an array containing dictionary entries with a string key, and a variant value *a(iiss)*: an array containing a struct with two integers and two strings *aai*: an array of arrays containing integers