Class to connect postgres with python in psycopg2

For we need to connect the postgres db in project very frequently, so write the follows class:

import psycopg2
#finish the work with task schedule
class dbwork:
    def __init__(self,work_content,dbname='taskschedule',user='rl_dev',password='123456', host='10.0.39.46',port=5432):
        self.dbname=dbname
        self.user=user
        self.password=password
        self.host=host
        self.port=port
        self.work_content=work_content
    def dowork(self):
        conn=psycopg2.connect(database=self.dbname , user=self.user, password=self.password,host=self.host,port=self.port)
        # Open a cursor to perform database operations
        cur=conn.cursor()
        # Execute a command: this creates a new table
        sqlstr=self.work_content
        #print 'sqlstr:'+sqlstr
        if sqlstr.__contains__("update") or sqlstr.__contains__("UPDATE") or sqlstr.__contains__("delete") or sqlstr.__contains__("DELETE") or sqlstr.__contains__("insert") or sqlstr.__contains__("INSERT"):
            cur.execute(sqlstr)
            #if the sql action is a transaction, need to do commit
            conn.commit()
            cur.close()
            conn.close()
        else:
            #if the sql action is not a transaction , return the result derectly
            cur.execute(self.work_content)
            result = cur.fetchall()
              cur.close()
            conn.close()
            
            return result

        #cur.execute("CREATE TABLE test (id serial PRIMARY KEY, num integer, data varchar);")