Method with_keys

src/repr/src/relation.rs:320–325

(mut self, keys: Vec<Vec<usize>>)

    }

    pub fn with_keys(mut self, keys: Vec<Vec<usize>>) -> Self {
        for key in keys {
            self = self.with_key(key)
        }
        self
    }

    /// Computes the number of columns in the relation.
    pub fn arity(&self) -> usize {