title: For loop stuck on first iteration, and others don't return correctly
body: <p>I am stuck.</p>
  <p>I'm trying to convert user input of 9 letters and convert them to numbers coinciding with the numbers 0-9 (like a phone).</p>
  <p>So far, my letters list object works, but when it gets to the for loop in the 'letter_converter' function, it will only return ['2','2'...] and won't continue through the entirety of the loop, for any other letter from the 'letters' list, the number won't return anything other than the '2', and for all else: it returns 'None'.</p>
  <p>Can someone help me with why this is? I'm more looking for the logic behind the answer because I am brand new to coding.</p>
  <pre><code>def phone_number_converter():
  
      '''This program will take user input to convert nine letters
      to a phone number using the text numbers from a phone number'''
  
      def letter_list():
          #takes 9 character string of user input and adds them to a list
          #returns: list object 'letters'
          word_input = input('Input nine letters: ')
          word = word_input
          letters = []
          for letter in word:
              letters.append(letter)
          return letters
  
      def letter_converter(letters):
          #takes a list object with separate strings and converts them to '0 - 9'
          #returns:list object called 'numbers'
          n = len(letters)
          numbers = []
          
          for letter in letters:
              while (len(numbers)) &lt; n:
                  if letter == 'a' or 'b' or 'c':
                      numbers.append('2')
                  elif letter == 'd' or 'e' or 'f':
                      numbers.append('3')
                  elif letter == 'g' or 'h' or 'i':
                      numbers.append('4')
                  elif letter == 'j' or 'k' or 'l':
                      numbers.append('5')
                  elif letter == 'm' or 'n' or 'o':
                      numbers.append('6')
                  elif letter == 'p' or 'q' or 'r' or 's':
                      numbers.append('7')
                  elif letter == 't' or 'u' or 'v':
                      numbers.append('8')
                  else:
                      numbers.append('9')    
          return numbers
      letters = letter_list()
      numbers = letter_converter(letters)
      return numbers 
  print(phone_number_converter())}
  </code></pre>