input: Write a function to set up GPIO pins, import necessary modules, define operating modes, prompt for password and mode selection, check license validity and user registration, calculate BAC, open solenoid to dispense beer if valid license and BAC below threshold, and record swipe data in appropriate file.
  def dispense_beer():
      # Setting up GPIO pins
      from time import sleep
      import RPi.GPIO as GPIO
  
      GPIO.setmode(GPIO.BOARD)  # Identifies the pin numbers to the pi
      GPIO.setwarnings(False)
  
      GPIO.setup(3, GPIO.OUT)  # Should sets pin #3 as an output...but doesnt work yet
      GPIO.setup(3, GPIO.LOW)  # Turns initial output for pin 3 off
  
      import time
      timestr = time.strftime("%Y%m%d %H%M%S")
  
      # Import functions to analyze license validity from CheckLicense.py
      from CheckLicense import check_license, calc_BAC
  
      import getpass
      import sys
      import re
  
      # Operating modes
      while True:
          mode_req = input("Enter Mode(normal, party, barkeep): ")
  
          if mode_req == "party":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "party"
                  break
          if mode_req == "normal":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "normal"
                  break
          if mode_req == "barkeep":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "barkeep"
                  break
  
      # Normal mode operations
      if mode == 'normal':
          print('{0} mode!'.format(mode))
          raw_text = getpass.getpass('Swipe card now:   ').strip()
          check_license_out = check_license(raw_text)
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
          DL_num = check_license_out[3]
  
          # Check to see if person is registered user
          users = open("users_list.txt", 'r')
          hit = 0
          if valid_license == 'Yes':
              for line in users:
                  if re.search(DL_num, line, re.IGNORECASE):
                      hit += 1
              if hit >= 1:
                  valid_license = 'Yes'
              else:
                  print('Not registered user')
                  valid_license = 'No'
  
          # Calculating the BAC
          BAC = calc_BAC(raw_text)
          print(BAC)
  
          # Opening the solenoid
          if valid_license == 'Yes':
              GPIO.setup(3, GPIO.HIGH)
              print('Beer time!')
              sleep(2)
              GPIO.setup(3, GPIO.LOW)
              with open("swipes.txt", "a") as myfile:
                  myfile.write(last_name + "," + first_name + " ")
                  myfile.write(DL_num + " ")
                  myfile.write(mode + " ")
                  myfile.write(time.strftime("%Y-%m-%d") + " ")
                  myfile.write(str(time.time()) + "\n")
  
      # Party mode operations
      elif mode == "party":
          print('{0} mode!'.format(mode))
          raw_license_text = getpass.getpass('Swipe card now:   ').strip()
          check_license_out = check_license(raw_license_text)
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
  
          # Opening the solenoid
          if valid_license == 'Yes':
              GPIO.setup(3, GPIO.HIGH)
              print('Beer time!')
              sleep(2)
              GPIO.setup(3, GPIO.LOW)
              with open("swipes_normal.txt", "a") as myfile:
                  myfile.write(last_name)
                  myfile.write(",")
                  myfile.write(first_name)
                  myfile.write(",")
                  myfile.write(time.strftime("%Y%m%d%H%M%S\n"))
  
      # Barkeep mode operations
      elif mode == "barkeep":
          print('{0} mode!'.format(mode))
          check_license_out = check_license(getpass.getpass('Swipe card now:   ').strip())
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
  
          # Check to see if person is blacklisted
          blacklist = open("blacklist.txt", 'r')
          hit = 0
          if valid_license == 'Yes':
              for line in blacklist:
                  if re.search(last_name, line, re.IGNORECASE):
                      hit += 1
                  if re.search(first_name, line, re.IGNORECASE):
                      hit += 1
              if hit >= 2:
                  print("We don't serve your kind here.")
                  blacklisted = 'Yes'
              else:
                  blacklisted = 'No'
  
          # Calculate BAC
          BAC = calc_BAC(raw_text)
  
          # Opening the solenoid
          if blacklisted == 'No':
              if BAC < intoxicated:
                  GPIO.setup(3, GPIO.HIGH)
                  print('Beer time!')
                  print(BAC)
                  sleep(2)
                  GPIO.setup(3, GPIO.LOW)
                  with open("swipes_barkeep.txt", "a") as myfile:
                      myfile.write(last_name)
                      myfile.write(",")
                      myfile.write(first_name)
                      myfile.write("_")
                      myfile.write(time.strftime("%Y-%m-%d %H:%M%S\n"))
              else:
                  print('Your BAC is {0}'.format(BAC))
                  print("You are too drunk, beer time is over")
  
  # Test cases
  assert dispense_beer() == "Beer time!"
  assert dispense_beer() == "Not registered user"
  assert dispense_beer() == "We don't serve your kind here."
  assert dispense_beer() == "Your BAC is 0.1"
output: def dispense_beer():
      from time import sleep
      import RPi.GPIO as GPIO
      GPIO.setmode(GPIO.BOARD)
      GPIO.setwarnings(False)
      GPIO.setup(3, GPIO.OUT)
      GPIO.setup(3, GPIO.LOW)
      import time
      timestr = time.strftime("%Y%m%d %H%M%S")
      from CheckLicense import check_license, calc_BAC
      import getpass
      import sys
      import re
      while True:
          mode_req = input("Enter Mode(normal, party, barkeep): ")
          if mode_req == "party":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "party"
                  break
          if mode_req == "normal":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "normal"
                  break
          if mode_req == "barkeep":
              passwd = getpass.getpass("Enter password: ")
              if passwd == "admin":
                  mode = "barkeep"
                  break
      if mode == 'normal':
          print('{0} mode!'.format(mode))
          raw_text = getpass.getpass('Swipe card now:   ').strip()
          check_license_out = check_license(raw_text)
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
          DL_num = check_license_out[3]
          users = open("users_list.txt", 'r')
          hit = 0
          if valid_license == 'Yes':
              for line in users:
                  if re.search(DL_num, line, re.IGNORECASE):
                      hit += 1
              if hit >= 1:
                  valid_license = 'Yes'
              else:
                  print('Not registered user')
                  valid_license = 'No'
          BAC = calc_BAC(raw_text)
          print(BAC)
          if valid_license == 'Yes':
              GPIO.setup(3, GPIO.HIGH)
              print('Beer time!')
              sleep(2)
              GPIO.setup(3, GPIO.LOW)
              with open("swipes.txt", "a") as myfile:
                  myfile.write(last_name + "," + first_name + " ")
                  myfile.write(DL_num + " ")
                  myfile.write(mode + " ")
                  myfile.write(time.strftime("%Y-%m-%d") + " ")
                  myfile.write(str(time.time()) + "\n")
      elif mode == "party":
          print('{0} mode!'.format(mode))
          raw_license_text = getpass.getpass('Swipe card now:   ').strip()
          check_license_out = check_license(raw_license_text)
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
          if valid_license == 'Yes':
              GPIO.setup(3, GPIO.HIGH)
              print('Beer time!')
              sleep(2)
              GPIO.setup(3, GPIO.LOW)
              with open("swipes_normal.txt", "a") as myfile:
                  myfile.write(last_name)
                  myfile.write(",")
                  myfile.write(first_name)
                  myfile.write(",")
                  myfile.write(time.strftime("%Y%m%d%H%M%S\n"))
      elif mode == "barkeep":
          print('{0} mode!'.format(mode))
          check_license_out = check_license(getpass.getpass('Swipe card now:   ').strip())
          valid_license = check_license_out[0]
          first_name = check_license_out[1]
          last_name = check_license_out[2]
          blacklist = open("blacklist.txt", 'r')
          hit = 0
          if valid_license == 'Yes':
              for line in blacklist:
                  if re.search(last_name, line, re.IGNORECASE):
                      hit += 1
                  if re.search(first_name, line, re.IGNORECASE):
                      hit += 1
              if hit >= 2:
                  print("We don't serve your kind here.")
                  blacklisted = 'Yes'
              else:
                  blacklisted = 'No'
          BAC = calc_BAC(raw_text)
          if blacklisted == 'No':
              if BAC < intoxicated:
                  GPIO.setup(3, GPIO.HIGH)
                  print('Beer time!')
                  print(BAC)
                  sleep(2)
                  GPIO.setup(3, GPIO.LOW)
                  with open("swipes_barkeep.txt", "a") as myfile:
                      myfile.write(last_name)
                      myfile.write(",")
                      myfile.write(first_name)
                      myfile.write("_")
                      myfile.write(time.strftime("%Y-%m-%d %H:%M%S\n"))
              else:
                  print('Your BAC is {0}'.format(BAC))
                  print("You are too drunk, beer time is over")