From 69731b653d3362634556394677a7b76cdf81cde7 Mon Sep 17 00:00:00 2001
From: lenak25 <lenak25@gmail.com>
Date: Tue, 13 Mar 2018 18:42:28 +0200
Subject: [PATCH] BLD: revert hourly freq support reported at issue #227

---
 catalyst/examples/simple_loop.py | 2 +-
 catalyst/exchange/exchange.py    | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/catalyst/examples/simple_loop.py b/catalyst/examples/simple_loop.py
index 99822b70..bc356e0a 100644
--- a/catalyst/examples/simple_loop.py
+++ b/catalyst/examples/simple_loop.py
@@ -26,7 +26,7 @@ def handle_data(context, data):
         context.asset,
         fields='price',
         bar_count=20,
-        frequency='2H'
+        frequency='30T'
     )
     last_traded = prices.index[-1]
     log.info('last candle date: {}'.format(last_traded))
diff --git a/catalyst/exchange/exchange.py b/catalyst/exchange/exchange.py
index c86b8cdd..73593c6d 100644
--- a/catalyst/exchange/exchange.py
+++ b/catalyst/exchange/exchange.py
@@ -13,6 +13,7 @@ from catalyst.exchange.exchange_errors import MismatchingBaseCurrencies, \
     PricingDataNotLoadedError, \
     NoDataAvailableOnExchange, NoValueForField, \
     NoCandlesReceivedFromExchange, \
+    InvalidHistoryFrequencyAlias,  \
     TickerNotFoundError, NotEnoughCashError
 from catalyst.exchange.utils.datetime_utils import get_delta, \
     get_periods_range, \
@@ -508,6 +509,10 @@ class Exchange:
             frequency, data_frequency, supported_freqs=['T', 'D', 'H']
         )
 
+        if unit == 'H':
+            raise InvalidHistoryFrequencyAlias(
+                freq=frequency)
+
         # we want to avoid receiving empty candles
         # so we request more than needed
         # TODO: consider defining a const per asset