moved publication to models. import classes from models

interface/TextMiningService.py

 from abc import ABCMeta, abstractmethod
 from typing import List
-
-
-class Publication:
-    def __init__(self, pmc_id=None, pm_id=None, doi=None, preprint_id=None, other_id=None):
-        self.pmc_id = pmc_id
-        self.pm_id = pm_id
-        self.doi = doi
-        self.preprint_id = preprint_id
-        self.other_id = other_id
-
+from models.publication import Publication
+from models.coocurrence import CoOccurrence
 
 class TextMiningService(metaclass=ABCMeta):