saving_compressed_array. Maybe useful later on.

    def save_node(self, h5file_holder, group_path, section_name, variables, 
                  detail=''):
        """Save a node to the h5file.
        h5file_holder: The holder of the h5file
        group_path: Where in the hierarchy the leaf has to be saved
        section_name: The name of the section which the variables belong to
        variables: The dictionary of the variable
        """
        found = False
        target_group = None
        for group in h5file_holder.walkGroups(group_path):
            if group._v_name == section_name:
                target_group = group
                found = True
                break
        if not found:
            target_group = h5file_holder.createGroup(group_path, section_name)
        
        filters = tables.Filters(complevel=5, complib='lzo')

        for var, vec in variables.iteritems():
                array = np.array(vec.to_python())
                atom = tables.Atom.from_dtype(array.dtype)
                shape = array.shape
                ca = h5file_holder.createCArray(target_group, 
                                                var, 
                                                atom,
                                                shape, 
                                                title = detail, 
                                                filters=filters
                                                )
                ca[:] = array # filling the array.