Function merklebtree::iterator::prev

pub fn prev<T>(btree_iterator: &mut btree_iterator<T>) -> bool where
    T: PartialEq + PartialOrd + Ord + Clone + Debug + CalculateHash, 

Prev moves the iterator to the previous element and returns true if there was a previous element in the container. If Prev() returns true, then previous element's key and value can be retrieved by Key() and Value(). Modifies the state of the iterator.