input: Write a function to determine if a given string is a subsequence of another string. If it is, return True, else return False.
  
  def is_subsequence(str1, str2):
      i = 0
      j = 0
      
      while(i < len(str1) and j < len(str2)):
          if str1[i] == str2[j]:
              i += 1
          j += 1
      
      return i == len(str1)
  
  assert is_subsequence("abc", "qaxbcy")==True
  assert is_subsequence("abc", "abracadabra")==True
  assert is_subsequence("abc", "qwerty")==False
  assert is_subsequence("hello", "hell")==False
  assert is_subsequence("", "any")==True
output: def is_subsequence(str1, str2):
      i = 0
      j = 0
      
      while(i < len(str1) and j < len(str2)):
          if str1[i] == str2[j]:
              i += 1
          j += 1
      
      return i == len(str1)