Python - Typeerror: 'List' Object Is Not Callable [Closed]

I'm trying to write a text file that has a list of rearranged alphabets so that each begins with a different character. The first letter is moved to the end, repeat.

    alphabet = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']

    # generate 26 alpabets without typing all
    def alpha_gen(alphabet,a_list):
       x = 0
       while x < 26:
           alphabet += [alphabet.pop(0)]
           key = alphabet(0)
           written = str(key) + ' : ' + str(alphabet) + '\n'
           a_list.write(written)
           x += 1

    def main():
       a_list = open('alpabet_list.txt', 'w')
       alpha_gen(alphabet, a_list)
       a_list.close()

    if __name__ == '__main__': main()

But I get this error:

    File "vigenere_cipher.py", line 13, in alpha_gen
    key = alphabet(0)
    TypeError: 'list' object is not callable