input: Write a function to determine if the first string is a subsequence of the second 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', 'qaxycz')==False
  assert is_subsequence('abc', 'aabbbcc')==True
  assert is_subsequence('xyz', 'xasdz')==False
  assert is_subsequence('', 'anyword')==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)