input: from typing import Tuple
  
  def num_common_chars(str1: str, str2: str) -> int:
      """Given two strings, find the total number of common characters present in both strings.
      >>> num_common_chars("hello", "world")
      3
      >>> num_common_chars("python", "java")
      1
      """
output:     set1 = set(str1)
      set2 = set(str2)
      common_chars = set1 & set2
      return len(common_chars)