polish readme

README.md

@@ -34,7 +34,7 @@ sheet.write('hello.xlsx')
 
 See, it's pretty simple and clear.
 
-Sample for rendering a simple table
+Sample for rendering a simple table.
 
 ```python
 class Record(NamedTuple):
@@ -43,20 +43,25 @@ class Record(NamedTuple):
     remark: str
 
 data = [
-    Record(name=f"name {i}", desc=f"desc {i}", remark=f"remark {i}") for i in range(3)]
-headers = [('name', '名称'), ('desc', '描述'), ('remark', '备注')]
-sheet = Sheet(root=
-Table(
-    data=data,
-    headers=headers,
-    cell_width=20,
-    cell_style={
-        "bg_color: yellow": lambda record, attr: attr == 'name' and record.name == 'name 1'
-    },
-    date_format="yyyy-mm-dd",
-    align="center",
-    border=1,
-))
+    Record(name=f"name {i}", desc=f"desc {i}", remark=f"remark {i}")
+    for i in range(3)
+]
+headers = [("name", "名称"), ("desc", "描述"), ("remark", "备注")]
+sheet = Sheet(
+    root=Table(
+        data=data,
+        headers=headers,
+        cell_width=20,
+        cell_style={
+            "bg_color: yellow": lambda record, attr: attr == "name"
+            and record.name == "name 1"
+        },
+        date_format="yyyy-mm-dd",
+        align="center",
+        border=1,
+    )
+)
+sheet.write('table.xlsx')
 ```