Private/Get-SharedMBXs.ps1

function Get-SharedMBXs{
    <#
        .SYNOPSIS
        Gets PrimarySmtpAddress of all Shared Mailboxes stored on Exchange Online server.
        .DESCRIPTION
        Gets PrimarySmtpAddress of all Shared Mailboxes stored on Exchange Online server.
        .EXAMPLE
        Get-SharedMBXs
        .OUTPUTS
        Syste.Array
    #>


    $MBXs = Get-EXOMailbox -RecipientTypeDetails SharedMailbox -ResultSize Unlimited | Select-Object PrimarySmtpAddress

    return $MBXs

}