Unnecessary iteration
Iteration when only one item is needed from list is inefficient and can make your code difficult to read.
def find_string_noncompliant():
    data = set(["sampleString1", "sampleString2", "sampleString3"])
    # Noncompliant: a loop is used to access a single item.
    for i in data:
        if i == "sampleString1":
            print("found item")
def find_string_compliant():
    data = set(["sampleString1", "sampleString2", "sampleString3"])
    # Compliant: a loop is not used to access a single item.
    if "sampleString1" in data:
        print("found item")