Get a list of all mechanical system type names

Hey everyone i want to get a list of the created mechanical system type names in revit. How would i do this.

Ex: Supply air, Return Air, Exhaust air

I also dont want to have to select an existing element. or how do i modify this python script to not create a new system type if the name already exists. Please let me know if this is possible.

import clr

from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Mechanical import *
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

doc = DocumentManager.Instance.CurrentDBDocument


mech_sys_type = MechanicalSystemType.Create(doc, MEPSystemClassification.SupplyAir , 'Duct 


OUT = mech_sys_type

never mind dumb question…