add docs for get_block_gas_details and fix nit for panic

src/fork.rs

@@ -645,17 +645,26 @@ impl ForkDetails {
         );
     }
 
+    /// Returns
+    ///
+    /// - `l1_gas_price`
+    /// - `l2_fair_gas_price`
+    /// - `fair_pubdata_price`
+    ///
+    /// for the given l2 block.
     pub fn get_block_gas_details(&self, miniblock: u32) -> Option<(u64, u64, u64)> {
         let res_opt_block_details = self.fork_source.get_block_details(L2BlockNumber(miniblock));
         match res_opt_block_details {
             Ok(opt_block_details) => opt_block_details.map(|block_details| {
                 (
                     block_details.base.l1_gas_price,
                     block_details.base.l2_fair_gas_price,
-                    block_details
-                        .base
-                        .fair_pubdata_price
-                        .expect("fair pubdata price is not present in block details"),
+                    block_details.base.fair_pubdata_price.unwrap_or_else(|| {
+                        panic!(
+                            "fair pubdata price is not present in {} l2 block details",
+                            miniblock
+                        )
+                    }),
                 )
             }),
             Err(e) => {