[gcode_macro LOAD_FILAMENT]
gcode:
    {% set speed = params.SPEED|default(300) %}
    {% set max_velocity = printer.configfile.settings['extruder'].max_extrude_only_velocity %}
    M300 # beep
    G91
    G92 E0
    G1 E350 F{max_velocity}
    G1 E25 F{speed} #purge
    M300
    M300

[gcode_macro UNLOAD_FILAMENT]
gcode:
    {% set speed = params.SPEED|default(500) %}
    G91
    G1 E-400 F{speed}
    G1 E-400 F{speed}
    G92