use meaningful names for identifiers try to choose names that can be read aloudand choose names that reflect the actionresponsibilityor data each identifier is naming classes (other than python' built-in classesshould have name that serves as singular nounand should be capitalized ( date rather than date or dateswhen multiple words are concatenated to form class namethey should follow the so-called "camelcaseconvention in which the first letter of each word is capitalized ( creditcardfunctionsincluding member functions of classshould be lowercase if multiple words are combinedthey should be separated by underscores ( make paymentthe name of function should typically be verb that describes its affect howeverif the only purpose of the function is to return valuethe function name may be noun that describes the value ( sqrt rather than calculate sqrtnames that identify an individual object ( parameterinstance variableor local variableshould be lowercase noun ( priceoccasionallywe stray from this rule when using single uppercase letter to designate the name of data structures (such as tree tidentifiers that represent value considered to be constant are traditionally identified using all capital letters and with underscores to separate words ( max sizerecall from our discussion of encapsulation that identifiers in any context that begin with single leading underscore ( secretare intended to suggest that they are only for "internaluse to class or moduleand not part of public interface use comments that add meaning to program and explain ambiguous or confusing constructs in-line comments are good for quick explanationsthey are indicated in python following the characteras in if = is odd multiline block comments are good for explaining more complex code sections in pythonthese are technically multiline string literalstypically delimited with triple quotes (""")which have no effect when executed in the next sectionwe discuss the use of block comments for documentation