old_contents: import json
  import os
  import re
  
  IP_REGEX = re.compile(r'(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})')
  
  
  def find_ips(filename):
      """Returns all the unique IPs found within a file."""
      matches = []
      with open(filename) as f:
          for line in f:
              match = IP_REGEX.findall(line)
              if match:
                  matches += match
      return set(sorted(matches)) if matches else set()
  
  
  def store_ips(cache_path, ips):
      """Stores the IPs into a cache for later retrieval."""
      cache = []
      if os.path.exists(cache_path):
          with open(cache_path, 'rb') as f:
              cache = json.loads(f.read())
      new_ips = 0
      existing_ips = [i['ip'] for i in cache]
      for ip in ips:
          if ip not in existing_ips:
              cache.append({'ip': ip})
              new_ips += 1
      with open(cache_path, 'wb') as f:
          f.write(json.dumps(cache))
      return new_ips
  
new_contents: import json
  import os
  import re
  
  IP_REGEX = re.compile(r'(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})')
  
  
  def find_ips(filename):
      """Returns all the unique IPs found within a file."""
      matches = []
      with open(filename) as f:
          for line in f:
              matches += IP_REGEX.findall(line)
      return set(sorted(matches)) if matches else set()
  
  
  def store_ips(cache_path, ips):
      """Stores the IPs into a cache for later retrieval."""
      cache = []
      if os.path.exists(cache_path):
          with open(cache_path, 'rb') as f:
              cache = json.loads(f.read())
      new_ips = 0
      existing_ips = [i['ip'] for i in cache]
      for ip in ips:
          if ip not in existing_ips:
              cache.append({'ip': ip})
              new_ips += 1
      with open(cache_path, 'wb') as f:
          f.write(json.dumps(cache))
      return new_ips
  
subject: Remove unnecessary check, used to re functions returning different types