def subtract(oEditor, blanklist, toollist, KeepOriginals=False):
    """
    Subtract the specified objects.
    
    Parameters
    ----------
    oEditor : pywin32 COMObject
        The HFSS editor in which the operation will be performed.        
    partlist : list
        List of part name strings to be subtracted.
    toollist : list
        List of part name strings to subtract from partlist.
    KeepOriginals : bool
        Whether to clone the tool parts.
    
    Returns
    -------
    objname : str
        Name of object created by the subtract operation
    """
#    blankliststr = ""
#    for item in blanklist:
#        blankliststr += (',' + item)
#        
#    toolliststr = ""
#    for item in toollist:
#        toolliststr += (',' + item)
    
    subtractselectionsarray = ["NAME:Selections", 
                               "Blank Parts:=", ','.join(blanklist), 
                               "Tool Parts:=", ','.join(toollist)]
    
    subtractparametersarray = ["NAME:SubtractParameters", 
                               "KeepOriginals:=", KeepOriginals]
    
    oEditor.Subtract(subtractselectionsarray, subtractparametersarray)
    
    return blanklist[0]