PowerShell 5 class: Import module needed for type - powershell

Question

I have a written a PowerShell 5 class:
class ConnectionManager
{
# Public Properties
static [String] $SiteUrl
static [System.Management.Automation.PSCredential] $Credentials
static [SharePointPnP.PowerShell.Commands.Base.SPOnlineConnection] $Connection
...
}
The type "SharePointPnP.PowerShell.Commands.Base.SPOnlineConnection" is from a custom (installed module), named "SharePointPnPPowerShell2016"
My class is inside another module/file, called "connection.manager.psm1".
When I load this module to make use of this class, it returns me the following error:
> Import-Module connection.manager.psm1
At connection.manager.psm1:6 char:11
+ static [SharePointPnP.PowerShell.Commands.Base.SPOnlineConnection] ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Unable to find type
[SharePointPnP.PowerShell.Commands.Base.SPOnlineConnection].
When I manually load the (PNP) module in the PowerShell session before loading my module it is loaded correctly and I can use it.
But I don't want to always have to manually load the other module first before I use my module. I tried to import the PNP-Module directly inside my module by adding:
Import-Module "SharePointPnPPowerShell2016"
at the beginning, before the class declaration, but it changes nothing, the error "Unable to find type" still appears.
Any ideas how to do this correctly?

Answer 1

I think you can fix this problem by using a module manifest
There is a "Required Module" and a "required Assembly" section you could use. This should handle loading the requirements (as long as they are installed) when you load your custom module, which holds the class.

Answer 2

If you have declared a class in a module, you cannot use it if you Import-Module; that only brings in cmdlets, functions, and aliases. Instead, your script should Using module the module; that will bring in the class as well as the other exported items.
(I actually misread the problem; this does not work to solve the querent's specific problem - but for a class that does not use classes from other modules, this will allow importing of classes from modules. The querent has found a known issue in PowerShell; see the comments for further information.)