lifetime parameters or bounds on method to_mdb_value do not match the trait declaration

[comfix]

While compilation got this error.

error[E0195]: lifetime parameters or bounds on method `to_mdb_value` do not match the trait declaration
  --> /home/comfix/.cargo/registry/src/github.com-1ecc6299db9ec823/lmdb-rs-0.7.1/src/traits.rs:55:5
   |
55 | /     fn to_mdb_value<'b, 's>(&'s self) -> MdbValue<'b> {
56 | |         unsafe {
57 | |             MdbValue::new(mem::transmute(self.as_ptr()),
58 | |                           self.len())
59 | |         }
60 | |     }
   | |_____^ lifetimes do not match trait