Update src/challenge.rs

src/challenge.rs

@@ -56,10 +56,7 @@ impl<F: PrimeField, S: CryptographicSponge> ChallengeGenerator<F, S> {
  }
  }
 
- /// Returns the sponge state if `self` is multivariate.
- ///
- /// ## Panics
- /// This function will panic if `self` is univariate.
+ /// Returns the sponge state if `self` is multivariate. Returns `None` otherwise.
  pub fn into_sponge(self) -> Option<S> {
  match self {
  Self::Multivariate(s, _) => Some(s),