Trying to understand UnmappedInstanceError using SQLAlchemy

I am trying to populate a table in SQL with data in the dataframe below. The code functions as expected when I use other data frames with exactly the same columns and data types, but only for this data block only, the error is sqlalchemy.orm.exc.UnmappedInstanceError: Class 'builtins.list' is not mapped

obtained from the string session.add([yc_node_hist(fk_yc_update = listofindices3[i],curve_date = row1['Date'], tenor = row1['Year'], Abrv = row1['VALUE'])])

. I am using automap()

to map a table yc_node_hist

to a class. My main problem is that I cannot figure out what exactly "Error" means .

             Date        Year      VALUE     ABBRV
0      2005-01-04  0.08333333   4.709456      GBP
1      2005-01-05  0.08333333   4.713099      GBP
2      2005-01-06  0.08333333   4.707237      GBP
3      2005-01-07  0.08333333   4.705043      GBP

      

        
        
        
      

    

yc_node_hist

:

create table yc_node_hist
(
    id bigint IDENTITY(1,1) PRIMARY KEY,
    fk_yc_update bigint NOT NULL FOREIGN KEY REFERENCES yc_update(id),
    curve_date date NOT NULL,
    tenor float NOT NULL,
    Abrv float NOT NULL
)

      

        
        
        
      

    

The code I'm using:

engine2 = YieldData.Connectionengine()
session = Session(bind=engine, expire_on_commit=False)
for (i1, row1), (i2, row2) in pairwise(df.iterrows()):
    if row1['ABBRV'] == row2['ABBRV'] and isinstance(row1['VALUE'], float)==1:
        print(row1)
        session.add([yc_node_hist(fk_yc_update = listofindices3[i],curve_date = row1['Date'], tenor = row1['Year'], Abrv = row1['VALUE'])])