The announcement period (measured in number of blocks) required of the initial proxy. Will generally be zero.
A positive, non-zero disambiguation index, in case this is called multiple times in the same
transaction (e.g. with utility::batch). Unless you're using batch you probably just
want to use 0.
The type of the proxy that the sender will be registered as over the
new account. This will almost always be the most permissive ProxyType possible to
allow for maximum flexibility. (ProxyType variants vary by runtime.)
Base Argument object for methods.