Check if there are any grand parents.
        
        Set the grandparents id:s
        
        Arguments:
            mother (Individual): An Individual object that represents the mother
            father (Individual): An Individual object that represents the father

def check_grandparents(self, mother = None, father = None):
        """
        Check if there are any grand parents.
        
        Set the grandparents id:s
        
        Arguments:
            mother (Individual): An Individual object that represents the mother
            father (Individual): An Individual object that represents the father
        
        
        """
        if mother:
            if mother.mother != '0':
                self.grandparents[mother.mother] =  ''
            elif mother.father != '0':
                self.grandparents[mother.father] = ''
        if father:
            if father.mother != '0':
                self.grandparents[father.mother] =  ''
            elif father.father != '0':
                self.grandparents[father.father] = ''
        return