public ExternalLocation getExtLocation(Address externalAddr) {
		if (externalAddr.getAddressSpace() != AddressSpace.EXTERNAL_SPACE) {
			throw new IllegalArgumentException("Expected external address");
		}
		lock.acquire();
		try {
			Symbol[] symbols = symbolMgr.getSymbols(externalAddr);
			if (symbols.length == 1) {
				return new ExternalLocationDB(this, (MemorySymbol) symbols[0]);
			}
			if (symbols.length > 2) {
				throw new AssertException(
					"More than two symbols are not expected for external addresses: " +
						externalAddr);
			}
			return null;
		}
		finally {
			lock.release();
		}
	}
{@return the external location associated with the given external address or null}
@param externalAddr the external address.
@throws IllegalArgumentException if address is not external
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/external/ExternalManagerDB.java