add tick_interval to get_ticker_history as an optional parameter

freqtrade/exchange/bittrex.py

@@ -1,5 +1,5 @@
 import logging
-from typing import List, Dict
+from typing import List, Dict, Optional
 
 import requests
 from bittrex.bittrex import Bittrex as _Bittrex
@@ -20,14 +20,11 @@ class Bittrex(Exchange):
     BASE_URL: str = 'https://www.bittrex.com'
     TICKER_METHOD: str = BASE_URL + '/Api/v2.0/pub/market/GetTicks'
     PAIR_DETAIL_METHOD: str = BASE_URL + '/Market/Index'
-    # Ticker inveral
-    TICKER_INTERVAL: str = 'fiveMin'
-    # Sleep time to avoid rate limits, used in the main loop
-    SLEEP_TIME: float = 25
 
     @property
     def sleep_time(self) -> float:
-        return self.SLEEP_TIME
+        """ Sleep time to avoid rate limits, used in the main loop """
+        return 25
 
     def __init__(self, config: dict) -> None:
         global _API, _EXCHANGE_CONF
@@ -86,17 +83,24 @@ class Bittrex(Exchange):
             'last': float(data['result']['Last']),
         }
 
-    def get_ticker_history(self, pair: str):
-        url = self.TICKER_METHOD
+    def get_ticker_history(self, pair: str, tick_interval: int):
         headers = {
             # TODO: Set as global setting
             'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36'
         }
+
+        if tick_interval == 1:
+            interval = 'oneMin'
+        elif tick_interval == 5:
+            interval = 'fiveMin'
+        else:
+            raise ValueError('Cannot parse tick_interval: {}'.format(tick_interval))
+
         params = {
             'marketName': pair.replace('_', '-'),
-            'tickInterval': self.TICKER_INTERVAL,
+            'tickInterval': interval,
         }
-        data = requests.get(url, params=params, headers=headers).json()
+        data = requests.get(self.TICKER_METHOD, params=params, headers=headers).json()
         if not data['success']:
             raise RuntimeError('{message} params=({pair})'.format(
                 message=data['message'],