diff --git a/freqtrade/optimize/hyperopt.py b/freqtrade/optimize/hyperopt.py
index 1f50d9a16..73a04a8cb 100644
--- a/freqtrade/optimize/hyperopt.py
+++ b/freqtrade/optimize/hyperopt.py
@@ -28,7 +28,7 @@ from freqtrade.optimize.backtesting import Backtesting
 from freqtrade.optimize.hyperopt_auto import HyperOptAuto
 from freqtrade.optimize.hyperopt_interface import IHyperOpt  # noqa: F401
 from freqtrade.optimize.hyperopt_loss_interface import IHyperOptLoss  # noqa: F401
-from freqtrade.optimize.hyperopt_tools import HyperoptTools, hyperopt_parser
+from freqtrade.optimize.hyperopt_tools import HyperoptTools, hyperopt_serializer
 from freqtrade.optimize.optimize_reports import generate_strategy_stats
 from freqtrade.resolvers.hyperopt_resolver import HyperOptLossResolver, HyperOptResolver
 
@@ -167,7 +167,7 @@ class Hyperopt:
         """
         epoch[FTHYPT_FILEVERSION] = 2
         with self.results_file.open('a') as f:
-            rapidjson.dump(epoch, f, default=hyperopt_parser,
+            rapidjson.dump(epoch, f, default=hyperopt_serializer,
                            number_mode=rapidjson.NM_NATIVE | rapidjson.NM_NAN)
             f.write("\n")
 
diff --git a/freqtrade/optimize/hyperopt_tools.py b/freqtrade/optimize/hyperopt_tools.py
index 7a0b00d01..006bc4ce0 100755
--- a/freqtrade/optimize/hyperopt_tools.py
+++ b/freqtrade/optimize/hyperopt_tools.py
@@ -22,7 +22,7 @@ logger = logging.getLogger(__name__)
 NON_OPT_PARAM_APPENDIX = "  # value loaded from strategy"
 
 
-def hyperopt_parser(x):
+def hyperopt_serializer(x):
     if isinstance(x, np.integer):
         return int(x)
     return str(x)
@@ -60,7 +60,8 @@ class HyperoptTools():
         }
         logger.info(f"Dumping parameters to {filename}")
         rapidjson.dump(final_params, filename.open('w'), indent=2,
-                       default=hyperopt_parser, number_mode=rapidjson.NM_NATIVE | rapidjson.NM_NAN
+                       default=hyperopt_serializer,
+                       number_mode=rapidjson.NM_NATIVE | rapidjson.NM_NAN
                        )
 
     @staticmethod