/// Ensures that the entry is occupied by inserting the given value if it is
/// vacant.
///
/// Returns a mutable reference to the entry's value.
Ensures that the entry is occupied by inserting the given value if it is
vacant.

Returns a mutable reference to the entry's value.
Ensures that the entry is occupied by inserting the given value if it is vacant . Returns a mutable reference to the entry ' s value .
pub fn or_insert(self, default: V) -> &'a mut V {
        match self {
            Occupied(entry) => entry.into_mut(),
            Vacant(entry) => entry.insert(default),
        }
    }
pub fn or_insert ( self , default : V ) -> & ' a mut V { match self { Occupied ( entry ) => entry . into_mut ( ) , Vacant ( entry ) => entry . insert ( default ) , } }
Ensures that the entry is occupied by inserting the given value if it is
vacant.
Ensures that the entry is occupied by inserting the given value if it is vacant .
self
<not_specific>
default
V
<not_specific>