pep8: Fix E301 pep8 violations.

Fix "E301: expected (1 or 2) blank line" pep8 violations.

zerver/lib/test_helpers.py

@@ -80,6 +80,7 @@ def tornado_redirected_to_list(lst):
 def simulated_empty_cache():
     # type: () -> Generator[List[Tuple[str, Union[text_type, List[text_type]], text_type]], None, None]
     cache_queries = [] # type: List[Tuple[str, Union[text_type, List[text_type]], text_type]]
+
     def my_cache_get(key, cache_name=None):
         # type: (text_type, Optional[str]) -> Any
         cache_queries.append(('get', key, cache_name))
@@ -206,6 +207,7 @@ class POSTRequestMock(object):
 class HostRequestMock(object):
     """A mock request object where get_host() works.  Useful for testing
     routes that use Zulip's subdomains feature"""
+
     def __init__(self, host=settings.EXTERNAL_HOST):
         # type: (text_type) -> None
         self.host = host