Typeerror: expected string or buffer

Question

I’m trying to make an intersection between two arrays using the lib re, but is returning me the following output:

OUTPUT:

selectobj = filter(regex.search, result_psql) Typeerror: expected string or buffer

Explaining script:

diff_array = These are the elements that should be compared, it is an array generated within the script, with the function below:

diff_array = []
def diff(first, second):
    second = set(second)
    return [item for item in first if item not in second]

result_psql = elements are a select in the PSQL database

result_psql = cursorpost.fetchall()

SCRIPT:

for element in diff_array:
    regex = re.compile(r'.*'+element+'')
    selectobj = filter(regex.search, result_psql)
    print(selectobj)

GOAL:

I want to make an intersection between two arrays, where the elements that are similar should be returned, just as it is done with the LIKE of SQL