@Override
	public Symbol createLabel(Address addr, String name, SourceType source)
			throws IllegalArgumentException, InvalidInputException {
		return createLabel(addr, name, null, source);
	}
Internal method for creating external function symbol.
<p>
NOTE: Any name conflict concerns must be checked before invoking this method. 

@param addr the address for the new symbol
@param name the name of the new symbol
@param namespace the namespace for the new symbol (null may be specified for global
           namespace)
@param source the SourceType of the new symbol
@param externalProgramAddress associated external program memory address (may be null) 
@param originalImportName  original imported name (i.e., mangled name)
@return the new symbol
@throws IOException if IO error occurs
@throws InvalidInputException if the name contains illegal characters (i.e. space)
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolManager.java