fix e402 fixed method when import some modules (for #447)

autopep8.py

@@ -873,11 +873,19 @@ def fix_e401(self, result):
     def fix_e402(self, result):
         (line_index, offset, target) = get_index_offset_contents(result,
                                                                  self.source)
+        for i in range(1, 100):
+            line = "".join(self.source[line_index:line_index+i])
+            try:
+                generate_tokens("".join(line))
+            except (SyntaxError, tokenize.TokenError):
+                continue
+            break
         if not (target in self.imports and self.imports[target] != line_index):
             mod_offset = get_module_imports_on_top_of_file(self.source,
                                                            line_index)
-            self.source[mod_offset] = target + self.source[mod_offset]
-        self.source[line_index] = ''
+            self.source[mod_offset] = line + self.source[mod_offset]
+        for offset in range(i):
+            self.source[line_index+offset] = ''
 
     def fix_long_line_logically(self, result, logical):
         """Try to make lines fit within --max-line-length characters."""

test/test_autopep8.py

@@ -2416,6 +2416,29 @@ def test_e402_duplicate_module(self):
         with autopep8_context(line) as result:
             self.assertEqual(fixed, result)
 
+    def test_e402_import_some_modules(self):
+        line = """\
+a = 1
+from csv import (
+    reader,
+    writer,
+)
+import os
+print(os, reader, writer)
+import os
+"""
+        fixed = """\
+import os
+from csv import (
+    reader,
+    writer,
+)
+a = 1
+print(os, reader, writer)
+"""
+        with autopep8_context(line) as result:
+            self.assertEqual(fixed, result)
+
     def test_e501_basic(self):
         line = """\