Remove extern crate unneeded for Rust 2018
@@ -20,13 +20,6 @@ extern crate lexical;
#[macro_use]
extern crate log;
// extern crate env_logger;
-extern crate num_bigint;
-extern crate num_complex;
-extern crate num_integer;
-extern crate num_traits;
-extern crate serde;
-extern crate serde_json;
-extern crate statrs;
extern crate rustpython_parser;
#[macro_use]
