struct NGram(ValueType, int N = 1, Kind kind = Kind.saturated, Storage storage = Storage.denseDynamic, Symmetry symmetry = Symmetry.ordered, RequestedBinType = void, Range)
opAssign
(in NGram!(ValueType, N, kind, storage, symmetry, RequestedBinType, RhsRange) rhs )  if (
isInputRange!RhsRange
)
  if (
is(
RequestedBinType == 
void) || 
 isUnsigned!RequestedBinType
 || 
isFloatingPoint!RequestedBinType
)