Fix _abc_data pickle error in 3.7

freqtrade/strategy/__init__.py

@@ -12,8 +12,18 @@ def import_strategy(strategy: IStrategy, config: dict) -> IStrategy:
     Imports given Strategy instance to global scope
     of freqtrade.strategy and returns an instance of it
     """
+
     # Copy all attributes from base class and class
-    attr = deepcopy({**strategy.__class__.__dict__, **strategy.__dict__})
+
+    comb = {**strategy.__class__.__dict__, **strategy.__dict__}
+
+    # Delete '_abc_impl' from dict as deepcopy fails on 3.7 with
+    # `TypeError: can't pickle _abc_data objects``
+    # This will only apply to python 3.7
+    if '_abc_impl' in comb:
+        del comb['_abc_impl']
+
+    attr = deepcopy(comb)
     # Adjust module name
     attr['__module__'] = 'freqtrade.strategy'