code: def ec2_vpc_cidrblock(self, lookup, default=None):
      
      vpcs = EFAwsResolver.__CLIENTS["ec2"].describe_vpcs(Filters=[{
        'Name': 'tag:Name',
        'Values': [lookup]
      }])
      if len(vpcs.get("Vpcs")) > 0:
        return vpcs["Vpcs"][0]["CidrBlock"]
      else:
        return default
docs: Args:
        lookup - the friendly name of the VPC whose CIDR block we want
      Returns:
        The CIDR block of the named VPC, or default/None if no match found