diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c10e794
--- /dev/null
+++ b/README.md
@@ -0,0 +1,16 @@
+# FSRS-RS-Python
+
+Python bindings for fsrs-rs, use burn-rs, instead of pytorch.
+
+---
+
+## Usage
+
+see [example.py](./example.py)
+
+## Development
+
+```bash
+maturin develop
+python example.py
+```
diff --git a/src/lib.rs b/src/lib.rs
index 0aaa169..021e2a4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,7 +8,7 @@ impl FSRS {
     pub fn new() -> Self {
         Self(fsrs::FSRS::new(Some(&[])).unwrap())
     }
-    #[pyo3(signature=(current_memory_state,desired_retention,days_elapsed ))]
+    #[pyo3(signature=(current_memory_state,desired_retention,days_elapsed))]
     pub fn next_states(
         &self,
         current_memory_state: Option<MemoryState>,