flake8: fix ambiguous var names (#3674)

dvc/dagascii.py

@@ -95,7 +95,7 @@ class AsciiCanvas(object):
         self.cols = cols
         self.lines = lines
 
-        self.canvas = [[" "] * cols for l in range(lines)]
+        self.canvas = [[" "] * cols for line in range(lines)]
 
     def draw(self):
         """Draws ASCII canvas on the screen."""

tests/func/test_repro.py

@@ -1555,7 +1555,7 @@ def test_dvc_formatting_retained(tmp_dir, dvc, run_copy):
     # Add comments and custom formatting to DVC-file
     lines = list(map(_format_dvc_line, stage_path.read_text().splitlines()))
     lines.insert(0, "# Starting comment")
-    stage_text = "".join(l + "\n" for l in lines)
+    stage_text = "".join(line + "\n" for line in lines)
     stage_path.write_text(stage_text)
 
     # Rewrite data source and repro