from typing import Dict, Optional

#   The standard typing module allows the provision of type hints for
#   better maintainability, etc. Its uses are not required.

#   The first function is completed for you.
#   Complete the remaining four functions by replacing "pass" by your code.

#
#   def get_max_value(data_dict: Dict[str, int]) -> int:
#       find_max_value returns the maximum value of a dictionary 
#       in which the keys are strings and the values are integers.
#       The function accepts one argument: data_dict.
#       The argument is a dictionary in which the key is a string and 
#       value of an integer (i.e., (data_dict: Dict[str, int])).
#       It returns an integer value (i.e., -> int)
#
#       It is ok to use just this:
#   def get_max_value(data_dict):
def get_max_value(data_dict: Dict[str, int]) -> Optional[int]:
    """Calculates the maximum of all integer values in the dictionary."""
    if len(data_dict) == 0:
        return None
    else:
        return max(data_dict.values())

#
#   def get_total_sum(data_dict: Dict[str, int]) -> int:
#   
def get_total_sum(data_dict: Dict[str, int]) -> Optional[int]:
    """Calculates and return the sum of all integer values in the dictionary."""
    pass
    
#
#   def get_value_list(data_dict: Dict[str, int]) -> int:
#       get_value_list returns the list of values in data_dict.
#   
def get_value_list(data_dict: Dict[str, int]) -> list[int]:
    """returns the list of int values"""
    pass

def increment_all_values(data_dict: Dict[str, int], 
        increment_by: int = 1) -> Dict[str, int]:
    """Returns a new dictionary with all values incremented by the specified amount."""
    pass

def value_frequencies(data_dict: Dict[str, int]) -> Dict[int, int]:
    """return a dictionary of the frequency of each unique integer value in the dictionary data_dict."""
    pass