curry property
Converts a function with 4 positional arguments into a sequence of 4 functions taking a single argument.
Implementation
Map1<T1, Map1<T2, Map1<T3, Map1<T4, R>>>> get curry => (T1 arg1) =>
(T2 arg2) => (T3 arg3) => (T4 arg4) => this(arg1, arg2, arg3, arg4);