input: from typing import List
  
  def check_ipv4(ip_list: List[str]) -> List[bool]:
      """ Check if the given list of strings are valid IPv4 addresses.
      An IPv4 address should be in the form of 'x.x.x.x' where x is a number between 0 and 255.
      
      >>> check_ipv4(['192.168.1.1', '256.256.256.256', '1.2.3.4'])
      [True, False, True]
      >>> check_ipv4(['127.0.0.1', '0.0.0.0', '255.255.255.255'])
      [True, True, True]
      """
output:     results = []
      for ip in ip_list:
          parts = ip.split('.')
          if len(parts) != 4:
              results.append(False)
              continue
          valid = True
          for part in parts:
              if not part.isdigit() or not (0 <= int(part) <= 255):
                  valid = False
                  break
          results.append(valid)
      return results