Displaying duplicates in dictionary

[DeaD_EyE]

It's impossible to have with your code duplicates, because you're not creating duplicates.
I changed your code a litte bit (functionality is the same):

from pprint import pprint


src_base_path = "/data/infy"
year_mth = "2020-10-05"
folder_names = ["1", "2", "3"]
table_names = ["bt1", "bt2", "bt3"]

print(f"Tables to be processed: {table_names}")
print(f"Folders to be processed: {folder_names}")

src_path = "{0}/{1}/app_date={2}/source={3}/"
input_body = []
for folder_name in folder_names:
    for table_name in table_names:
        input_body.append(
            {
                "sourcePath": src_path.format(
                    src_base_path, table_name, year_mth, folder_name
                ),
                "tableName": table_name,
            }
        )


pprint(input_body)

A dict can have only unique keys. Putting stuff into a dict with the same key will overwrite the old value.