input: Write a function to create a dictionary containing student names and their corresponding marks. The function should take a dictionary as input and return the dictionary.
  assert create_student_marks_dict({'John': 90, 'Levi': 85, 'Jill': 95, 'Sara': 75})=={'John': 90, 'Levi': 85, 'Jill': 95, 'Sara': 75}
  assert create_student_marks_dict({'Alice': 88, 'Bob': 76})=={'Alice': 88, 'Bob': 76}
  assert create_student_marks_dict({})=={}
  assert create_student_marks_dict({'Charlie': 92})=={'Charlie': 92}
  assert create_student_marks_dict({'Emma': 80, 'Frank': 85, 'Grace': 90})=={'Emma': 80, 'Frank': 85, 'Grace': 90}
output: def create_student_marks_dict(student_marks):
      return student_marks