diff --git a/tkinter-enter.py b/tkinter-enter.py
index e632782..4a9f24d 100644
--- a/tkinter-enter.py
+++ b/tkinter-enter.py
@@ -3,7 +3,15 @@
 # importing tkinter
 
 import tkinter as tk
-from generic import sanitize, type_hosts_listed, type_hosts_organized, ip_lookup, domain_lookup, spf_dmarc
+from generic import (
+    sanitize,
+    type_hosts_listed,
+    type_hosts_organized,
+    ip_lookup,
+    domain_lookup,
+    spf_dmarc,
+)
+
 
 # function to run on pressing
 # 'ENTER' key from keyboard.
@@ -12,46 +20,47 @@ def key_handler_function(event):
     print(type(inputs))
     sanitized = sanitize.strip_and_list(inputs)
     typed = type_hosts_listed.type_hosts(sanitized)
-    textbox.insert('end', typed)
+    textbox.insert("end", typed)
     listed = type_hosts_organized.type_hosts(sanitized)
     # IPs = listed['IPs']
     # below works for updating a global variable (here)...
-    var.set(listed['IPs'])
-    ip_listbox.delete(0, 'end')
-    domain_listbox.delete(0, 'end')
-    url_listbox.delete(0, 'end')
-    email_listbox.delete(0, 'end')
+    var.set(listed["IPs"])
+    ip_listbox.delete(0, "end")
+    domain_listbox.delete(0, "end")
+    url_listbox.delete(0, "end")
+    email_listbox.delete(0, "end")
 
-    for IP in listed['IPs']:
+    for IP in listed["IPs"]:
         hostname = ip_lookup.get_hostname(IP)
         output = "{} => {}".format(IP, hostname[0])
-        ip_listbox.insert('end', output)
-    for domain in listed['domains']:
+        ip_listbox.insert("end", output)
+    for domain in listed["domains"]:
         ip = domain_lookup.get_ip_address(domain)
         output = "{} => {}".format(domain, ip)
-        domain_listbox.insert('end', output)
-    for URL in listed['URLs']:
-        url_listbox.insert('end', URL)
-    for email in listed['emails']:
+        domain_listbox.insert("end", output)
+    for URL in listed["URLs"]:
+        url_listbox.insert("end", URL)
+    for email in listed["emails"]:
         dmarc, spf = spf_dmarc.lookup(email)
         output_dmarc = "{} => {}".format(email, dmarc)
         output_spf = "{} => {}".format(email, spf)
-        email_listbox.insert('end', output_dmarc, output_spf)
+        email_listbox.insert("end", output_dmarc, output_spf)
 
 
 def test_button_function():
     # testing quoting and comma separating hosts, IPs for now, from global StringVar var
-    textbox.delete(1.0, 'end')
-    IPs = ', '.join([f'"{host}"' for host in var.get()])
-    textbox.insert('end', IPs)
+    textbox.delete(1.0, "end")
+    IPs = ", ".join([f'"{host}"' for host in var.get()])
+    textbox.insert("end", IPs)
     print("var is : {}".format(var.get()))
     # ... and printing an updated global variable here!
 
+
 # main application window
 root = tk.Tk()
 root.title("Enter IP addresses, URLs, domains, email addresses")
 root.geometry("900x600")
-root.resizable(0,0)
+root.resizable(0, 0)
 
 # configure the grid
 root.columnconfigure(0, weight=1)
@@ -59,7 +68,7 @@ root.columnconfigure(1, weight=1)
 root.columnconfigure(2, weight=1)
 root.columnconfigure(3, weight=1)
 
-#Listing stuff
+# Listing stuff
 
 # creating widgets
 entry = tk.Entry(root, text="Put in IP addresses, URLs, domains, email addresses")
@@ -72,29 +81,30 @@ domain_label = tk.Label(root, text="domain => IP")
 domain_listbox = tk.Listbox(root)
 url_label = tk.Label(root, text="URL => IP")
 url_listbox = tk.Listbox(root)
-email_label = tk.Label(root, text="email address => DMARC/SPF") 
+email_label = tk.Label(root, text="email address => DMARC/SPF")
 email_listbox = tk.Listbox(root)
-var =  tk.Variable()
-entrylabel.grid(column=1, row=0, columnspan=2, sticky='nsew')
-entry.grid(column=0, row=1, columnspan=4, sticky='nsew') 
-ip_label.grid(column=0, row=2, columnspan=2, sticky='nsew')
-ip_listbox.grid(column=0, row=3, columnspan=2, sticky='nsew')
-domain_label.grid(column=2, row=2, columnspan=2, sticky='nsew')
-domain_listbox.grid(column=2, row=3, columnspan=2, sticky='nsew')
-url_label.grid(column=0, row=4, columnspan=2, sticky='nsew')
-url_listbox.grid(column=0, row=5, columnspan=2, sticky='nsew')
-email_label.grid(column=2, row=4, columnspan=2, sticky='nsew')
-email_listbox.grid(column=2, row=5, columnspan=2, sticky='nsew')
+var = tk.Variable()
+entrylabel.grid(column=1, row=0, columnspan=2, sticky="nsew")
+entry.grid(column=0, row=1, columnspan=4, sticky="nsew")
+ip_label.grid(column=0, row=2, columnspan=2, sticky="nsew")
+ip_listbox.grid(column=0, row=3, columnspan=2, sticky="nsew")
+domain_label.grid(column=2, row=2, columnspan=2, sticky="nsew")
+domain_listbox.grid(column=2, row=3, columnspan=2, sticky="nsew")
+url_label.grid(column=0, row=4, columnspan=2, sticky="nsew")
+url_listbox.grid(column=0, row=5, columnspan=2, sticky="nsew")
+email_label.grid(column=2, row=4, columnspan=2, sticky="nsew")
+email_listbox.grid(column=2, row=5, columnspan=2, sticky="nsew")
 
 # label.grid(column=1, row=2)
 # textbox.grid(column=1, row=3)
 
-#Trying out buttons
-test_button = tk.Button(root, text="comma-separate and add quotes", command=test_button_function)
+# Trying out buttons
+test_button = tk.Button(
+    root, text="comma-separate and add quotes", command=test_button_function
+)
 
 # Binding ENTER key to function
 entry.bind("<Return>", key_handler_function)
 
 # run the application
 root.mainloop()
-