input: Write a python function to convert a string to its ASCII binary representation.
  assert ascii_conversion("Hello") == '0100100001100101011011000110110001101111'
  assert ascii_conversion("World") == '0101011101101111011100100110110001100100'
  assert ascii_conversion("Python") == '010100000111100101110100011010000110111101101110'
output: def ascii_conversion(s):
      return ''.join(format(ord(char), '08b') for char in s)