count_nodes             Search an xml file for a specific named node
                        and count the number of instances
extract_line_level_data
                        Open data from a single line metadata table
                        where it's zip or xml format
find_node_value         Search an xml file for a specific named mode
                        and return the value(s) stored in it
get_fares_metadata      Return fares metadata from the 'BODS' API
get_location_gtfs       Return GTFS-RT location data from the 'BODS'
                        API
get_location_xml        Return XML vehicle location data from the
                        'BODS' API
get_timetable_data      Extract line-level timetable data from all rows
                        of the provided metadata table
get_timetable_metadata
                        Return timetable metadata from the 'BODS' API
line_level_xml          Pull a table of relevant values from specified
                        nodes in the xml
noc_lookup              Lookup between operator names and national
                        operator code ('NOC') lookup
not_null                Join together a value and an associated API
                        string if the value is not NULL
not_null_date           Join together a date value and an associated
                        API string if the value is not NULL
open_all_xml            Open every xml file within a zip object and
                        extract data of interest from it using a given
                        function
poss_xml                Try to read an xml file using read_xml; where
                        this fails, quietly return a NULL value
xml_file_counter        Count the number of xml files included within a
                        provided metadata dataframe, whether the
                        provided file links are xml or zip
