console calculator

''' simple console based calculator '''

import operator as op

OPERATORS = {
            '**': op.pow,
            '^' : op.pow,
            '*' : op.mul,
            '/' : op.truediv,
            '//': op.floordiv,
            '+' : op.add,
            '-' : op.sub,
            '%' : op.mod,
            '<' : op.lt,
            '<=': op.le,
            '==': op.eq,
            '!=': op.ne,
            '>=': op.ge,
            '>' : op.gt,
}

def get_num(msg):
    ''' promt for and return numeric input - reject responses that are not integer or float '''
    while True:
        response = input(msg)
        value = None
        if response:
            try:
                value = float(response)
                value = int(response)  # float worked, try int
            except ValueError:  # either float or int cast failed
                pass
            if value or value is 0:  # if float worked, we will have a value
                return value
        print('integer or decimal input required. Please try again.')

def welcome():
    print('\n\nWelcome to this simple calculator\n\n')
    print('The following operators are understood:\n ')
    print(*OPERATORS)
    print('\nYou will be repeatedly asked to enter the operator you wish to use')
    print('and the two operands to apply the operator to.\n\n')
    print('To exit: just press enter/return without an operator\n\n')

welcome()
while True:  # master loop, input another calculation
    print()
    while True:  # valid operator input
        operator = input('What operation (symbol) ? ')
        if not operator or operator in OPERATORS:
            break
        print('Sorry. Not supported.')
    if not operator:
        break

    num1 = get_num('enter first operand: ')
    num2 = get_num('enter second operand: ')
    try:
        result = OPERATORS[operator](num1,num2)
    except ValueError as e:
        print(e)
    except TypeError as e:
        print(e)
    except ZeroDivisionError as e:
        print(e)
    else:
        print(f'{num1} {operator} {num2} = {result}')