Plot_profit.py: Fix Flake8 warnings

scripts/plot_profit.py

@@ -15,7 +15,6 @@ import sys
 import json
 from typing import Dict
 import numpy as np
-from datetime import datetime
 
 from plotly import tools
 from plotly.offline import plot
@@ -29,8 +28,6 @@ from freqtrade.logger import Logger
 import freqtrade.optimize as optimize
 import freqtrade.misc as misc
 
-import pprint
-
 
 logger = Logger(name="Graph profits").get_logger()
 
@@ -192,6 +189,7 @@ def define_index(min_date, max_date, interval):
     """
     return int((max_date - min_date) / (interval * 60))
 
+
 def plot_parse_args(args):
     """
     Parse args passed to the script