limit usage of ccxt to freqtrade/exchange only

freqtrade/data/converter.py

@@ -2,9 +2,9 @@
 Functions to convert data from one format to another
 """
 import logging
+
 import pandas as pd
 from pandas import DataFrame, to_datetime
-from freqtrade.misc import timeframe_to_minutes
 
 
 logger = logging.getLogger(__name__)
@@ -58,6 +58,8 @@ def ohlcv_fill_up_missing_data(dataframe: DataFrame, ticker_interval: str) -> Da
     using the previous close as price for "open", "high" "low" and "close", volume is set to 0
 
     """
+    from freqtrade.exchange import timeframe_to_minutes
+
     ohlc_dict = {
         'open': 'first',
         'high': 'max',

freqtrade/data/history.py

@@ -1,10 +1,10 @@
 """
 Handle historic data (ohlcv).
-includes:
+
+Includes:
 * load data for a pair (or a list of pairs) from disk
 * download data from exchange and store to disk
 """
-
 import logging
 from pathlib import Path
 from typing import Optional, List, Dict, Tuple, Any
@@ -15,8 +15,7 @@ from pandas import DataFrame
 from freqtrade import misc, OperationalException
 from freqtrade.arguments import TimeRange
 from freqtrade.data.converter import parse_ticker_dataframe
-from freqtrade.exchange import Exchange
-from freqtrade.misc import timeframe_to_minutes
+from freqtrade.exchange import Exchange, timeframe_to_minutes
 
 
 logger = logging.getLogger(__name__)