input: Write a function to construct a Python dictionary containing student names and marks as key-value pairs. The function should take a dictionary as input and return the constructed dictionary.
  
  def construct_student_marks(marks_dict):
      return marks_dict
  
  # Test cases
  assert construct_student_marks({"John": 90, "Levi": 85, "Jill": 95, "Sara": 75}) == {"John": 90, "Levi": 85, "Jill": 95, "Sara": 75}
  assert construct_student_marks({"Alice": 88, "Bob": 92, "Charlie": 78}) == {"Alice": 88, "Bob": 92, "Charlie": 78}
  assert construct_student_marks({}) == {}
output: def construct_student_marks(marks_dict):
      return marks_dict