def select_subsection_of_collection(collection_df, method_group):
    """
    Returns a dataframe which is the subset of rows of collecion dataframe that match the requested method category
    :param collection_df: Pandas DataFrame of submission collection.
    :param method_group: String that specifies with method group is requested. "Physical","Empirical","Mixed" or "Other"
    :return: Pandas DataFrame of subsection of submission collection.
    """

    print("Looking for submissions of selected method group...")
    print("Method group: {}".format(method_group))

    #print("Collection_df:\n",collection_df)

    # Filter collection dataframe based on method category
    #collection_df_of_selected_method_group = collection_df.loc[collection_df["reassigned category"] == method_group]
    collection_df_of_selected_method_group = collection_df.loc[collection_df["category"] == method_group]
    collection_df_of_selected_method_group = collection_df_of_selected_method_group.reset_index(drop=True)
    print("collection_df_of_selected_method_group: \n {}".format(collection_df_of_selected_method_group))

    return collection_df_of_selected_method_group