[WDI Indicator Download] Provide a default filename for WDI download (d…

…atacommonsorg#982)

* Provide a default filename for WDI download

* Adding a helpful print statement

scripts/world_bank/.gitignore

@@ -1 +1,2 @@
 preprocessed_source_csv
+download_indicators/*.csv

scripts/world_bank/wdi/download_indicators/wdi_download_indicators.py

@@ -9,7 +9,10 @@
 import numpy as np
 import pandas as pd
 
-_OUT_PATH = flags.DEFINE_string('out_path', None, 'CNS path to write output.')
+# The output path should have a default filename.
+_OUT_DEFAULT_NAME = 'cleaned_wdi.csv'
+_OUT_PATH = flags.DEFINE_string('out_path', _OUT_DEFAULT_NAME,
+                                'CNS path to write output.')
 
 indicators = [
     'SP.POP.TOTL',
@@ -72,6 +75,7 @@ def DownloadAndParseCsvs() -> None:
   """
     dat = []
     for indicator in indicators:
+        print(f'DOWNLOADING: {indicator}....')
         resp = urllib.request.urlopen(
             f'http://api.worldbank.org/v2/country/all/indicator/{indicator}?source=2&downloadformat=csv'
         )
@@ -121,6 +125,8 @@ def DownloadAndParseCsvs() -> None:
             'unit',
         ],
     )
+    # Write to the _OUT_PATH which defaults to the output filename
+    # if no path is provided.
     with open(_OUT_PATH.value, 'w+') as f_out:
         out_df.to_csv(f_out, index=False)