pub fn lock(&mut self) {
        if self.lock.is_none() {
            self.lock = Some(RefCell::new(HashMap::new()))
        } // if
    }
/// Lock prevents defining new rules in order to be able to utilze the rule cache and speed up
/// rule queries.
Lock prevents defining new rules in order to be able to utilze the rule cache and speed up
rule queries.
Lock prevents defining new rules in order to be able to utilze the rule cache and speed up rule queries .
pub fn lock(&mut self) {
        if self.lock.is_none() {
            self.lock = Some(RefCell::new(HashMap::new()))
        } // if
    }
pub fn lock ( & mut self ) { if self . lock . is_none ( ) { self . lock = Some ( RefCell :: new ( HashMap :: new ( ) ) ) } // if }
Lock prevents defining new rules in order to be able to utilze the rule cache and speed up
rule queries.
Lock prevents defining new rules in order to be able to utilze the rule cache and speed up rule queries .
&mut self
&mut self