code: List<SPFPersona> getAvailablePersonas() {
  		SQLiteDatabase db = getReadableDatabase();
  		String table = Contract.TABLE_PERSONAS;
  		String[] columns = { Contract.COLUMN_PERSONA };
  		String selection = null;
  		String[] selectionArgs = null;
  		String groupBy = null;
  		String having = null;
  		String orderBy = null;
  		Cursor c = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);
  		List<SPFPersona> availablePersonas = new ArrayList<SPFPersona>();
  		while (c.moveToNext()) {
  			String p = c.getString(c.getColumnIndex(Contract.COLUMN_PERSONA));
  			SPFPersona pers = new SPFPersona(p);
  			availablePersonas.add(pers);
  		}
  		c.close();
  		return availablePersonas;
  	}
docs: Returns the list of all the existing {@link SPFPersona}.
  
  @return the list of {@link SPFPersona}