'Create a new Virtual Private Cloud.
:type cidr_block: str
:param cidr_block: A valid CIDR block
:type instance_tenancy: str
:param instance_tenancy: The supported tenancy options for instances
launched into the VPC. Valid values are \'default\' and \'dedicated\'.
:type dry_run: bool
:param dry_run: Set to True if the operation should not actually run.
:rtype: The newly created VPC
:return: A :class:`boto.vpc.vpc.VPC` object'

def create_vpc(self, cidr_block, instance_tenancy=None, dry_run=False):

    params = {'CidrBlock': cidr_block}
    if instance_tenancy:
        params['InstanceTenancy'] = instance_tenancy
    if dry_run:
        params['DryRun'] = 'true'
    return self.get_object('CreateVpc', params, VPC)
