dateparser unexpected behaviour fix, now use the timestamp to convert numpy.datetime64 to datetime.datetime (#23)

use timestamp to convert numpy.datetime64

Author: Anand Sanmukhani

prometheus_api_client/metric.py

@@ -69,8 +69,8 @@ def __init__(self, metric, oldest_data_datetime=None):
             self.metric_values["ds"] = pandas.to_datetime(self.metric_values["ds"], unit="s")
 
         # Set the metric start time and the metric end time
-        self.start_time = dateparser.parse(str(self.metric_values["ds"].head(1).values[0]))
-        self.end_time = dateparser.parse(str(self.metric_values["ds"].tail(1).values[0]))
+        self.start_time = self.metric_values.iloc[0, 0]
+        self.end_time = self.metric_values.iloc[-1, 0]
 
     def __eq__(self, other):
         """
@@ -150,12 +150,8 @@ def __add__(self, other):
                 new_metric.metric_values = new_metric.metric_values.loc[mask]
 
             # Update the metric start time and the metric end time for the new Metric
-            new_metric.start_time = dateparser.parse(
-                str(new_metric.metric_values["ds"].head(1).values[0])
-            )
-            new_metric.end_time = dateparser.parse(
-                str(new_metric.metric_values["ds"].tail(1).values[0])
-            )
+            new_metric.start_time = new_metric.metric_values.iloc[0, 0]
+            new_metric.end_time = new_metric.metric_values.iloc[-1, 0]
 
             return new_metric