Add blank line for PEP8 compliance

Author: mgmarino

pandas/core/arrays/interval.py

@@ -1049,6 +1049,7 @@ def mid(self):
         points) and is either monotonic increasing or monotonic decreasing,
         else False.
         """
+
     # https://github.com/python/mypy/issues/1362
     # Mypy does not support decorated properties
     @property  # type: ignore