Update data.py

Author: toddbirchard

plotlydash_flask_tutorial/plotlydash/data.py

@@ -1,4 +1,6 @@
+"""Prepare data for Plotly Dash."""
 import pandas as pd
+import numpy as np
 
 
 def create_dataframe():
@@ -9,4 +11,4 @@ def create_dataframe():
     num_complaints = df['complaint_type'].value_counts()
     to_remove = num_complaints[num_complaints <= 30].index
     df.replace(to_remove, np.nan, inplace=True)
-    return df
+    return df