diff --git a/exercises/13_error_handling/errors6.rs b/exercises/13_error_handling/errors6.rs
index aaf0948e..8b63ff1f 100644
--- a/exercises/13_error_handling/errors6.rs
+++ b/exercises/13_error_handling/errors6.rs
@@ -10,6 +10,7 @@
 // hint.
 
 // I AM NOT DONE
+// NOTE: 重要
 
 use std::num::ParseIntError;
 
@@ -25,13 +26,26 @@ impl ParsePosNonzeroError {
         ParsePosNonzeroError::Creation(err)
     }
     // TODO: add another error conversion function here.
-    // fn from_parseint...
+    fn from_parseint(s: &str) -> Result<i64, ParsePosNonzeroError> {
+        match s.parse::<i64>() {
+            Ok(result) => {
+                if result == 0 {
+                    Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+                } else if result < 0 {
+                    Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+                } else {
+                    Ok(result)
+                }
+            },
+            Err(err) => Err(ParsePosNonzeroError::ParseInt(err))
+        }
+    }
 }
 
 fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
+    let x: i64 = ParsePosNonzeroError::from_parseint(s)?;
     PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
 }