input: from typing import List
  
  
  def is_subsequence(str1: str, str2: str) -> bool:
      """
      Check if the string str1 is a subsequence of the string str2.
      A subsequence is a sequence that can be derived from another sequence
      by deleting some or no elements without changing the order of the remaining elements.
      
      >>> is_subsequence("abc", "qaxbcy")
      True
      >>> is_subsequence("abc", "defghij")
      False
      >>> is_subsequence("abc", "aabbcc")
      True
      """
      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)
output:     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)