docs: def get_local_gb(iLOIP, snmp_credentials):
      """Gets the maximum disk size among all disks.
  
      :param iLOIP: IP address of the server on which SNMP discovery
                    has to be executed.
      :param snmp_credentials in a dictionary having following mandatory
             keys.
             auth_user: SNMP user
             auth_protocol: Auth Protocol
             auth_prot_pp: Pass phrase value for AuthProtocol.
             priv_protocol:Privacy Protocol.
             auth_priv_pp: Pass phrase value for Privacy Protocol.
      """
      disk_sizes = _get_disksize_MiB(iLOIP, snmp_credentials)
      max_size = 0
      for uuid in disk_sizes:
          for key in disk_sizes[uuid]:
              if int(disk_sizes[uuid][key]) > max_size:
                  max_size = int(disk_sizes[uuid][key])
      max_size_gb = max_size/1024
      return max_size_gb