Retrieves entries from all people/tasks logged to this project.

        Can be filtered based on time by specifying start/end datetimes.

def entries(self, start = None, end = None):
        '''Retrieves entries from all people/tasks logged to this project.

        Can be filtered based on time by specifying start/end datetimes.'''
        if not start:
            start = self.earliest_record
        if not end:
            end = self.latest_record
        fr = start.strftime('%Y%m%d')
        to = end.strftime('%Y%m%d')
        url = str.format(
            'projects/{}/entries?from={}&to={}',
            self.id,
            fr,
            to,
        )
        response = self.hv.get_request(url)
        return [Entry(self.hv, ej['day_entry']) for ej in response]