====== declareProperty ======
===== Idea =====
In your python options file, you may want to pass values to a certain used C++ class (e.g. in DaVinci in the TupleToolMCTruth you may want to switch on the association by Chi2 or not). 
===== Example =====
The following example treats the case, if you want to pass a string to your C++ class (to save output, for instance).

===== Additions to your .h-file =====
In the .h-file of your class, add:
<code>
private:
  std::string m_outputName;
</code>
Of course, it does not necessarily need to be private.

===== Additions to your .cpp-file =====
In the **constructor**, add:
<code>
declareProperty( "OutputName", m_outputName = "defaultOutputName");
</code>
The first argument defines the name in the python options file, the second argument sets the variable to a default value, if there is no input from the python options file.

In the **initialize()** add (for example):
<code>
fstream out = new fstream(m_outputName, ios::out);
</code>

**Note:** Only add the ''declareProperty'' in the constructor, but don't do anything with the variable, it won't work (at least considering my experience...)

===== Additions to your python options file =====
To your instance of your class, add:
<code>
myInstance.OutputName = "myOutputName.txt"
</code>