Encoding troubles with python, mysql and utf8mb4

I get the following warnings, when trying to save a simple dataframe to mysql.:

C:...\anaconda3\lib\site-packages\pymysql\cursors.py:170: Warning: (1366, "Incorrect string value: '\x92\xE9t\xE9)' for column 'VARIABLE_VALUE' at row 518") result = self._query(query)

And

C:...anaconda3\lib\site-packages\pymysql\cursors.py:170: Warning: (3719, "'utf8' is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous.") result = self._query(query)

Environment info : I use Mysql8, python3.6 (pymysql 0.9.2, sqlalchemy 1.2.1)

I visited posts like the one linked bellow, none of which seem to give a solution as to how to avoid this warning.

• MySQL “incorrect string value” error when save unicode string in Django -> Indication is to use UTF8

N.B : The Collation in the table within mysql doesn't seem to be set to the one I specified in the create_db function within the Connection class.

The executable code:

import DataEngine.db.Connection as connection
import random
import pandas as pd

if __name__ == "__main__":
    conn = connection.Connection(host="host_name", port="3306", user="username", password="password")
    conn.create_db("raw_data")
    conn.establish("raw_data")
    l1 = []
    for i in range(10):
        l_nested = []
        for j in range(10):
            l_nested.append(random.randint(0, 100))
        l1.append(l_nested)
    df = pd.DataFrame(l1)

    conn.save(df, "random_df")
    df2 = conn.retrieve("random_df")
    print(df2)

So the dataframe that is persisted in the database is :

   index   0   1   2   3   4   5   6   7   8   9
0      0  11  57  75  45  81  70  91  66  93  96
1      1  51  43   3  64   2   6  93   5  49  40
2      2  35  80  76  11  23  87  19  32  13  98
3      3  82  10  69  40  34  66  42  24  82  59
4      4  49  74  39  61  14  63  94  92  82  85
5      5  50  47  90  75  48  77  17  43   5  29
6      6  70  40  78  60  29  48  52  48  39  36
7      7  21  87  41  53  95   3  31  67  50  30
8      8  72  79  73  82  20  15  51  14  38  42
9      9  68  71  11  17  48  68  17  42  83  95

My Connection class

import sqlalchemy
import pymysql
import pandas as pd


class Connection:
    def __init__(self: object, host: str, port: str, user: str, password: str):
        self.host = host
        self.port = port
        self.user = user
        self.password = password
        self.conn = None

    def create_db(self: object, db_name: str, charset: str = "utf8mb4", collate:str ="utf8mb4_unicode_ci",drop_if_exists: bool = True):
        c = pymysql.connect(host=self.host, user=self.user, password=self.password)
        if drop_if_exists:
            c.cursor().execute("DROP DATABASE IF EXISTS " + db_name)
        c.cursor().execute("CREATE DATABASE " + db_name + " CHARACTER SET=" + charset + " COLLATE=" + collate)
        c.close()
        print("Database %s created with a %s charset" % (db_name, charset))

    def establish(self: object, db_name: str, charset: str = "utf8mb4"):
        self.conn = sqlalchemy.create_engine(
            "mysql+pymysql://" + self.user + ":" + self.password + "@" + self.host + ":" + self.port + "/" + db_name +
            "?charset=" + charset)
        print("Connection with database : %s has been established as %s at %s." % (db_name, self.user, self.host))
        print("Charset : %s" % charset)

    def retrieve(self, table):
        df = pd.read_sql_table(table, self.conn)
        return df

    def save(self: object, df: "Pandas.DataFrame", table: str, if_exists: str = "replace", chunksize: int = 10000):
        df.to_sql(name=table, con=self.conn, if_exists=if_exists, chunksize=chunksize)

Some elements that might help: