class Employee:

    def __init__(self, first, last, pay):
        self.first = first
        self.last = last
        self.email = first + '.' + last + '@email.com'
        self.pay = pay

    def fullname(self):
        return '{} {}'.format(self.first, self.last)

    @classmethod
    def from_string(cls, emp_str):
        first, last, pay = emp_str.split('-')
        return cls(first, last, pay)

    @staticmethod
    def is_workday(day):
        return not day == 7

# emp_1 = Employee('Masoud', 'Sadrnezhaad', 5000)
emp_1 = Employee.from_string('Masoud-Sadrnezhaad-5000')

print(Employee.is_workday(7))