====== GetSystemPartnerTNr ======
 
This function can be executed without parameters, only by running job and takes the //TNr// of the //SystemPartners// from the data of the //Document object//. Otherwise, a GLN can simply be passed to the function, for which the corresponding TNr is returned. 

==== Syntax: ====

<code>GetTradingPartnerTNr('GLN')</code>

==== Sample: ====

<code>GetTradingPartnerTNr('4043077000005')</code>