@Override
	public ExternalLocation getUniqueExternalLocation(Namespace namespace, String label) {
		Set<ExternalLocation> externalLocations = getExternalLocations(namespace, label);
		if (externalLocations.size() == 1) {
			return externalLocations.iterator().next();
		}
		return null;
	}
Get the external location which best matches the specified parameters.
Preference is given to extLabel over extAddr
@param library the library namespace containing this external location.
@param extLabel the name of the external location. Can be null.
@param extAddr the address of function in the external program.  Can be null
@return the best matching ExternalLocation or null.
@throws InvalidInputException if the extLabel name contains illegal characters (i.e. space)
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/external/ExternalManagerDB.java