diff --git a/src/common.rs b/src/common.rs
index 7953543..9842e9a 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -7,7 +7,7 @@ pub enum IpNetworkError {
     InvalidCidrFormat(String),
 }
 
-pub fn cidr_parts<'a>(cidr: &'a str) -> Result<(&'a str, &'a str), IpNetworkError> {
+pub fn cidr_parts(cidr: &str) -> Result<(&str, &str), IpNetworkError> {
     let parts = cidr.split('/').collect::<Vec<&str>>();
     if parts.len() == 2 {
         Ok((parts[0], parts[1]))
diff --git a/src/ipv4.rs b/src/ipv4.rs
index bb95d57..59f1379 100644
--- a/src/ipv4.rs
+++ b/src/ipv4.rs
@@ -341,8 +341,7 @@ mod test {
         let mut map = HashMap::new();
         let net = Ipv4Network::new(Ipv4Addr::new(127, 0, 0, 1), 16).unwrap();
         map.insert(net, 137);
-        let out = map.get(&net).unwrap();
-        assert_eq!(137, *out);
+        assert_eq!(137, map[&net]);
     }
 
     #[test]
diff --git a/src/ipv6.rs b/src/ipv6.rs
index 0f2acfa..3ccad72 100644
--- a/src/ipv6.rs
+++ b/src/ipv6.rs
@@ -83,8 +83,7 @@ impl FromStr for Ipv6Network {
     type Err = IpNetworkError;
     fn from_str(s: &str) -> Result<Ipv6Network, IpNetworkError> {
         let (addr_str, prefix_str) = cidr_parts(s)?;
-        let addr = Ipv6Addr::from_str(addr_str)
-            .map_err(|_| IpNetworkError::InvalidAddr(format!("{}", addr_str)))?;
+        let addr = Ipv6Addr::from_str(addr_str).map_err(|_| IpNetworkError::InvalidAddr(addr_str.to_string()))?;
         let prefix = parse_prefix(prefix_str, IPV6_BITS)?;
         Ipv6Network::new(addr, prefix)
     }