def nr_cases(self, snv_cases=None, sv_cases=None):
        """Return the number of cases in the database

        Args:
            snv_cases(bool): If only snv cases should be searched
            sv_cases(bool): If only snv cases should be searched

        Returns:
            cases (Iterable(Case)): A iterable with mongo cases
        """
        query = {}
        
        if snv_cases:
            query = {'vcf_path': {'$exists':True}}
        if sv_cases:
            query = {'vcf_sv_path': {'$exists':True}}
        if snv_cases and sv_cases:
            query = None

        return self.db.case.count_documents(query)
Return the number of cases in the database

        Args:
            snv_cases(bool): If only snv cases should be searched
            sv_cases(bool): If only snv cases should be searched

        Returns:
            cases (Iterable(Case)): A iterable with mongo cases