Replacing a column in a dataframe raises ValueError: Columns must be same length as key - pandas

Question

There is a description of using the replace method:
[https://www.geeksforgeeks.org/replace-values-of-a-dataframe-with-the-value-of-another-dataframe-in-pandas/][1]
Unfortunately, I have an error during replacing columns of dataframe with a column from another dataframe.
import pandas as pd
# initialise data of lists.
colors = {
"first_set": ["99", "88", "77", "66", "55", "44", "33", "22"],
"second_set": ["1", "2", "3", "4", "5", "6", "7", "8"],
}
color = {
"first_set": ["a", "b", "c", "d", "e", "f", "g", "h"],
"second_set": ["VI", "IN", "BL", "GR", "YE", "OR", "RE", "WI"],
}
# Calling DataFrame constructor on list
df = pd.DataFrame(colors, columns=["first_set", "second_set"])
df1 = pd.DataFrame(color, columns=["first_set", "second_set"])
# Display the Output
display(df)
display(df1)
Here is a code with an error:
# replace column of one DataFrame with
# the column of another DataFrame
ser1 = df1["first_set"]
ser2 = df["second_set"]
print(ser1)
print(ser2)
df["second_set"] = df1.replace(to_replace=ser1, value=ser2)
--------------------------------------------------------------------------- ValueError Traceback (most recent call
last) ~\AppData\Local\Temp/ipykernel_28648/2104797653.py in
5 print(ser1)
6 print(ser2)
----> 7 df['second_set'] = df1.replace(to_replace=ser1,value=ser2)
~.virtualenvs\01_python_packages-rD-UbwAe\lib\site-packages\pandas\core\frame.py
in setitem(self, key, value) 3600
self._setitem_array(key, value) 3601 elif isinstance(value,
DataFrame):
-> 3602 self._set_item_frame_value(key, value) 3603 elif ( 3604 is_list_like(value)
~.virtualenvs\01_python_packages-rD-UbwAe\lib\site-packages\pandas\core\frame.py
in _set_item_frame_value(self, key, value) 3727
len_cols = 1 if is_scalar(cols) else len(cols) 3728 if
len_cols != len(value.columns):
-> 3729 raise ValueError("Columns must be same length as key") 3730 3731 # align right-hand-side columns
if self.columns
ValueError: Columns must be same length as key