diff --git a/downloader/downloader/main.py b/downloader/downloader/main.py
index b7fa10a..fddce06 100644
--- a/downloader/downloader/main.py
+++ b/downloader/downloader/main.py
@@ -5,7 +5,6 @@ import hashlib
 import logging
 import os
 import signal
-import sys
 import uuid
 from base64 import b64encode
 from contextlib import contextmanager
@@ -55,7 +54,7 @@ class TimedOutError(Exception):
 
 
 @contextmanager
-def soft_hard_timeout(logger, description, (soft_timeout, hard_timeout), on_soft_timeout):
+def soft_hard_timeout(logger, description, timeouts, on_soft_timeout):
 	"""Context manager that wraps a piece of code in a pair of timeouts,
 	a "soft" timeout and a "hard" one. If the block does not complete before
 	the soft timeout, the given on_soft_timeout() function is called in a new greenlet.
@@ -70,6 +69,7 @@ def soft_hard_timeout(logger, description, (soft_timeout, hard_timeout), on_soft
 	retrying, even as the original code continues to hold out in hope the call eventually
 	succeeds.
 	"""
+	soft_timeout, hard_timeout = timeouts
 	# Finished is set after we're done to flag to the pending soft timeout callback
 	# that it shouldn't run.
 	finished = False
@@ -214,7 +214,7 @@ class StreamsManager(object):
 			fetch_time = monotonic()
 			with soft_hard_timeout(self.logger, "fetching master playlist", self.FETCH_TIMEOUTS, self.trigger_refresh):
 				master_playlist = twitch.get_master_playlist(self.channel)
-			new_urls = twitch.get_media_playlist_uris(master_playlist, self.stream_workers.keys())
+			new_urls = twitch.get_media_playlist_uris(master_playlist, list(self.stream_workers.keys()))
 			self.update_urls(fetch_time, new_urls)
 			for quality, workers in self.stream_workers.items():
 				# warn and retry if the url is missing
@@ -260,9 +260,11 @@ class StreamsManager(object):
 			# wait min retry interval with jitter, unless we're stopping
 			self.stopping.wait(common.jitter(self.FETCH_MIN_INTERVAL))
 		self.logger.info("Stopping workers")
-		for workers in self.stream_workers.values():
+		stream_workers = list(self.stream_workers.values())
+		for workers in stream_workers:
 			for worker in workers:
 				worker.stop()
+		for workers in stream_workers:
 			for worker in workers:
 				worker.done.wait()
 
@@ -510,7 +512,7 @@ class SegmentGetter(object):
 			partial: Segment is incomplete. Hash is included.
 			temp: Segment has not been downloaded yet. A random uuid is added.
 		"""
-		arg = str(uuid.uuid4()) if type == "temp" else b64encode(hash.digest(), "-_").rstrip("=")
+		arg = str(uuid.uuid4()) if type == "temp" else b64encode(hash.digest(), b"-_").encode().rstrip("=")
 		return "{}-{}-{}.ts".format(self.prefix, type, arg)
 
 	def exists(self):
@@ -519,10 +521,10 @@ class SegmentGetter(object):
 		try:
 			candidates = os.listdir(dirname)
 		except OSError as e:
-			# on ENOENT (doesn't exist), return []
+			# on ENOENT (doesn't exist), return false
 			if e.errno != errno.ENOENT:
 				raise
-			return []
+			return False
 		full_prefix = "{}-full".format(self.prefix)
 		return any(candidate.startswith(full_prefix) for candidate in candidates)
 
@@ -563,17 +565,14 @@ class SegmentGetter(object):
 					for chunk in resp.iter_content(8192):
 						f.write(chunk)
 						hash.update(chunk)
-		except Exception:
-			# save original exception so we can re-raise it later even though we may be handling
-			# another exception in the interim
-			ex_type, ex, tb = sys.exc_info()
+		except Exception as e:
 			if file_created:
 				partial_path = self.make_path("partial", hash)
 				self.logger.warning("Saving partial segment {} as {}".format(temp_path, partial_path))
 				common.rename(temp_path, partial_path)
 				segments_downloaded.labels(type="partial", channel=self.channel, quality=self.quality).inc()
 				segment_duration_downloaded.labels(type="partial", channel=self.channel, quality=self.quality).inc(self.segment.duration)
-			raise ex_type, ex, tb
+			raise e
 		else:
 			request_duration = monotonic() - start_time
 			segment_type = "full" if request_duration < self.FETCH_SUSPECT_TIME else "suspect"