'Create the volume in the specified storage group.
:param array: the array serial number
:param storagegroup_name: the group name (String)
:param srp: the SRP (String)
:param slo: the SLO (String)
:param workload: the workload (String)
:param do_disable_compression: flag for disabling compression
:param extra_specs: additional info
:returns: storagegroup_name - string'

def create_storage_group(self, array, storagegroup_name, srp, slo, workload, extra_specs, do_disable_compression=False):

    srp_id = (srp if slo else 'None')
    payload = {'srpId': srp_id, 'storageGroupId': storagegroup_name, 'emulation': 'FBA'}
    if slo:
        slo_param = {'num_of_vols': 0, 'sloId': slo, 'workloadSelection': workload, 'volumeAttribute': {'volume_size': '0', 'capacityUnit': 'GB'}}
        if do_disable_compression:
            slo_param.update({'noCompression': 'true'})
        elif self.is_compression_capable(array):
            slo_param.update({'noCompression': 'false'})
        payload.update({'sloBasedStorageGroupParam': [slo_param]})
    (status_code, job) = self._create_storagegroup(array, payload)
    self.wait_for_job('Create    storage    group', status_code, job, extra_specs)
    return storagegroup_name
