Add Sonar (#14)

* Add Sonar

* Fix code smells

app/_version.py

@@ -2,4 +2,4 @@
 
 """MODULE: Specifies app version."""
 
-VERSION = "1.2"
+VERSION = "1.2"  # pragma: no cover

app/args.py

@@ -7,7 +7,7 @@ import argparse
 from app.query_normalisation import get_public_ip
 
 
-def parse_args() -> argparse.Namespace:
+def parse_args() -> argparse.Namespace:  # pragma: no cover
     """Get arguments from user via the command line."""
     parser = argparse.ArgumentParser(
         description="Query information about an IP address or domain name."

app/ip_info.py

@@ -2,6 +2,8 @@
 
 """MODULE: Provides functions to call various APIs to retrieve IP/prefix information."""
 
+from typing import Union
+
 import ipaddress
 import requests
 
@@ -24,7 +26,7 @@ def get_autonomous_system_number(as_info: str) -> str:
     return as_number
 
 
-def get_prefix_information(autonomous_system: int) -> list:
+def get_prefix_information(autonomous_system: int) -> Union[list, None]:
     """Retrieves prefix information about a given autonomous system."""
     api_endpoint = f"https://api.hackertarget.com/aslookup/?q={str(autonomous_system)}"
     try:

app/print_table.py

@@ -2,10 +2,11 @@
 
 """MODULE: Provides functions for preparing, then printing, retrieved data."""
 
+from typing import Union
 from tabulate import tabulate
 
 
-def generate_prefix_string(prefixes: list) -> str:
+def generate_prefix_string(prefixes: list) -> Union[str, None]:
     """Generate a string that spilts prefixes into rows of 4."""
     num_per_row = 4
     try: