pub trait Stringr {
// Required methods
fn remove_chars(&self, chars: HashSet<char>) -> String;
fn remove_whitespace(&self) -> String;
fn splitn(&self, n: usize) -> Vec<String>;
fn splitn_separator(&self, n: usize, separator: &str) -> String;
fn wildcard_match(
&self,
pattern: &str,
wildcard: &char,
single_wildcard: &char,
ignore_casing: bool
) -> bool;
}