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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def list_datacenters_via_proxy(datacenter_names=None, service_instance=None):
    '''
    Returns a list of dict representations of VMware datacenters.
    Connection is done via the proxy details.

    Supported proxies: esxdatacenter

    datacenter_names
        List of datacenter names.
        Default is None.

    service_instance
        Service instance (vim.ServiceInstance) of the vCenter.
        Default is None.

    .. code-block:: bash

        salt '*' vsphere.list_datacenters_via_proxy

        salt '*' vsphere.list_datacenters_via_proxy dc1

        salt '*' vsphere.list_datacenters_via_proxy dc1,dc2

        salt '*' vsphere.list_datacenters_via_proxy datacenter_names=[dc1, dc2]
    '''
    if not datacenter_names:
        dc_refs = salt.utils.vmware.get_datacenters(service_instance,
                                                    get_all_datacenters=True)
    else:
        dc_refs = salt.utils.vmware.get_datacenters(service_instance,
                                                    datacenter_names)

    return [{'name': salt.utils.vmware.get_managed_object_name(dc_ref)}
            for dc_ref in dc_refs]