Deletes a run from a desired project. If this causes the run_table to be empty then the entire project gets deleted
    :param project_name: String, project which contains the desire run_name
    :param run_name: String, run to delete

def drop_run(project_name, run_name):
    """
    Deletes a run from a desired project. If this causes the run_table to be empty then the entire project gets deleted
    :param project_name: String, project which contains the desire run_name
    :param run_name: String, run to delete
    """
    conn, c = open_data_base_connection()
    # delete all the variable tables first
    c.execute("SELECT variable_name FROM {}".format(run_name))
    try:
        all_variables = np.array(c.fetchall()).squeeze(axis=1)
        for i in all_variables:
            variable_table_name = run_name + '_' + i
            c.execute("""DROP TABLE IF EXISTS {}""".format(variable_table_name))
    except np.core._internal.AxisError:
        print("Did not find any values, so deleting run table directly.")

    c.execute("""DROP TABLE IF EXISTS {}""".format(run_name))
    c.execute("""DELETE FROM {} WHERE run_name='{}'""".format(project_name + '_run_table', run_name))

    # delete project if project_name+'_run_table' is empty
    c.execute("""SELECT run_name FROM {}""".format(project_name + '_run_table'))
    all_runs = c.fetchall()
    if len(all_runs) == 0:
        c.execute("""DROP TABLE IF EXISTS {}""".format(project_name + '_run_table'))
        c.execute("""DELETE FROM main_table WHERE project_name='{}'""".format(project_name))

    conn.commit()
    print("{} table deleted".format(run_name))