Quick servo code for the Beaglebone Black using the Adafruit BBIO python library and a Parallax Standard servo

servo.py

import Adafruit_BBIO.PWM as PWM

servo_pin = "P8_13"
duty_min = 2.5
duty_max = 13.1
duty_span = duty_max - duty_min

PWM.start(servo_pin, duty_span * 0.5, 60.0)

while True:
    angle = raw_input("Angle (0 to 180 x to exit):")
    if angle == 'x':
        PWM.stop(servo_pin)
        PWM.cleanup()
        break
    angle_f = float(angle)
    duty = ((angle_f / 180) * duty_span + duty_min)
    print "Setting duty to %.2f%%" % duty
    PWM.set_duty_cycle(servo_pin, duty)

This variation worked well for me. The adafruit tutorial does not offer much detail on this part.
Thank you so much for sharing. Im a little further along in better understanding PWM and servos.