AttributeError: 'DataModelPostgressql' object has no attribute 'conn'

Question

import psycopg2
import pandas as pd
class DataModelPostgressql():
    def __init__(self,host,port,databaseName,username,password):
        self.host=host
        self.port=port
        self.databaseName=databaseName
        self.username=username
        self.password=password

    def create_connection(self):
        conn = psycopg2.connect(
            database=self.databaseName, user=self.username, password=self.password, host=self.host, port=self.port
        )
        #cursor = self.conn.cursor()
        #return conn

    def queryResult(self,query):
        
        if self.conn:
            cur = self.conn.cursor()
            cur.execute(query)
            df = pd.DataFrame(cur.fetchall())

        return df

    def close_Connection(self):
        if self.conn:
            self.cursor.close()
            self.conn.close()
        

query="SELECT * FROM COMPANY"
Obj1= DataModelPostgressql('localhost',5432,'postgres','postgres','postgres')
Obj1.queryResult(query)

Having error like AttributeError: 'DataModelPostgressql' object has no attribute 'conn' I want to create a database connection in one method and read data from another method and close database connection with another method Please help me to solve this