Do not wrap exceptions in Exception

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rsmime"
-version = "0.3.0"
+version = "0.3.1"
 edition = "2021"
 
 [lib]

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "rsmime"
-version = "0.3.0"
+version = "0.3.1"
 classifiers = [
     "License :: OSI Approved :: MIT License",
     "Development Status :: 3 - Alpha",

rsmime.pyi

@@ -1,2 +1,11 @@
+class ReadCertificateError(Exception):
+    ...
+
+class LoadCertificateError(Exception):
+    ...
+
+class SignError(Exception):
+    ...
+
 def sign(cert_file: str, key_file: str, data_to_sign: bytes) -> str:
     ...

src/lib.rs

@@ -37,13 +37,8 @@ pub fn _sign(cert_file: &str, key_file: &str, data_to_sign: &[u8]) -> PyResult<V
 #[pyfunction]
 fn sign(cert_file: &str, key_file: &str, data_to_sign: Vec<u8>) -> PyResult<String> {
     match _sign(cert_file, key_file, &data_to_sign) {
-        Ok(signed_data) => {
-            match String::from_utf8(signed_data) {
-                Ok(signed_string) => Ok(signed_string),
-                Err(err) => Err(PyException::new_err(err))
-            }
-        },
-        Err(err) => Err(PyException::new_err(err.to_string())),
+        Ok(signed_data) => Ok(String::from_utf8(signed_data).expect("Failed to convert to string")),
+        Err(err) => Err(err),
     }
 }