This sample code is for Servo with Raspberry Pi Pico using CircuitPython

servoPico.py

import time
import board
import pwmio
from adafruit_motor import servo
 
# create a PWMOut object on Pin GP27.
pwm = pwmio.PWMOut(board.GP27, duty_cycle=2 ** 15, frequency=50)
 
# Create a servo object, my_servo.
my_servo = servo.Servo(pwm)
 
while True:
    for angle in range(0, 180, 5):  # 0 - 180 degrees, 5 degrees at a time.
        my_servo.angle = angle
        time.sleep(0.05)
    for angle in range(180, 0, -5): # 180 - 0 degrees, 5 degrees at a time.
        my_servo.angle = angle
        time.sleep(0.05)