BLD: optimize imports

catalyst/exchange/bittrex/bittrex.py

@@ -1,7 +1,7 @@
 import json
+import time
 
 import pandas as pd
-import time
 from catalyst.assets._assets import TradingPair
 from logbook import Logger
 from six.moves import urllib

catalyst/exchange/exchange_bundle.py

@@ -1,4 +1,30 @@
 import os
+import shutil
+from itertools import chain
+
+import pandas as pd
+from catalyst.assets._assets import TradingPair
+from logbook import Logger
+from pandas.tslib import Timestamp
+from pytz import UTC
+from six import itervalues
+
+from catalyst import get_calendar
+from catalyst.constants import LOG_LEVEL
+from catalyst.data.minute_bars import BcolzMinuteOverlappingData, \
+    BcolzMinuteBarMetadata
+from catalyst.exchange.bundle_utils import range_in_bundle, \
+    get_bcolz_chunk, get_delta, get_month_start_end, \
+    get_year_start_end, get_df_from_arrays, get_start_dt, get_period_label
+from catalyst.exchange.exchange_bcolz import BcolzExchangeBarReader, \
+    BcolzExchangeBarWriter
+from catalyst.exchange.exchange_errors import EmptyValuesInBundleError, \
+    TempBundleNotFoundError, \
+    NoDataAvailableOnExchange, \
+    PricingDataNotLoadedError
+from catalyst.exchange.exchange_utils import get_exchange_folder
+from catalyst.utils.cli import maybe_show_progress
+from catalyst.utils.paths import ensure_directory
 import os
 import shutil
 from itertools import chain

catalyst/exchange/poloniex/poloniex.py

@@ -1,4 +1,3 @@
-import calendar
 import json
 import json
 import time

tests/exchange/test_bundle.py

@@ -1,14 +1,13 @@
 import hashlib
+import os
 import tempfile
 from logging import getLogger
 
-import os
 import pandas as pd
 
 from catalyst import get_calendar
 from catalyst.exchange.bundle_utils import get_bcolz_chunk, \
-    get_periods_range, get_start_dt, get_month_start_end, get_df_from_arrays, \
-    get_year_start_end
+    get_start_dt, get_df_from_arrays
 from catalyst.exchange.exchange_bcolz import BcolzExchangeBarReader, \
     BcolzExchangeBarWriter
 from catalyst.exchange.exchange_bundle import ExchangeBundle, \