AttributeError: type object 'StandardSqlDataType' has no attribute 'STRING'

I want to load data from csv to BigQuery and it shows this error.

My code:

df.to_gbq(destination_table = '[dataset].[table]',project_id='projectname', if_exists = 'append')

Error:

~/opt/anaconda3/lib/python3.8/site-packages/google/cloud/bigquery/__init__.py in <module>
     33 __version__ = get_distribution("google-cloud-bigquery").version
     34 
---> 35 from google.cloud.bigquery.client import Client
     36 from google.cloud.bigquery.dataset import AccessEntry
     37 from google.cloud.bigquery.dataset import Dataset

~/opt/anaconda3/lib/python3.8/site-packages/google/cloud/bigquery/client.py in <module>
     56 from google.cloud.bigquery._helpers import _verify_job_config_type
     57 from google.cloud.bigquery._http import Connection
---> 58 from google.cloud.bigquery import _pandas_helpers
     59 from google.cloud.bigquery.dataset import Dataset
     60 from google.cloud.bigquery.dataset import DatasetListItem

~/opt/anaconda3/lib/python3.8/site-packages/google/cloud/bigquery/_pandas_helpers.py in <module>
     38     pyarrow = None
     39 
---> 40 from google.cloud.bigquery import schema
     41 
     42 

~/opt/anaconda3/lib/python3.8/site-packages/google/cloud/bigquery/schema.py in <module>
     26 # https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types
     27 LEGACY_TO_STANDARD_TYPES = {
---> 28     "STRING": types.StandardSqlDataType.STRING,
     29     "BYTES": types.StandardSqlDataType.BYTES,
     30     "INTEGER": types.StandardSqlDataType.INT64,

AttributeError: type object 'StandardSqlDataType' has no attribute 'STRING'

How can i fix this? I try a few recommendation like this. But still cannot works.

pip install `google-cloud-bigquery`

Is there any other way?

Thank you