def get_surfaces_per_volume(my_core, entityset_ranges):
    """
    Get the number of surfaces that each volume in a given file contains
    
    inputs
    ------
    my_core : a MOAB core instance
    entity_ranges : a dictionary of the entityset ranges of each tag in a file
    
    outputs
    -------
    s_p_v : a dictionary containing the volume entityhandle
            and the number of surfaces each volume in the file contains
            i.e. {volume entityhandle:surfaces it contains}
    """

    s_p_v = {}
    for volumeset in entityset_ranges['Volumes']:
        s_p_v[volumeset] = my_core.get_child_meshsets(volumeset).size()
    return s_p_v