when an identifier is indicated in commandpython searches series of namespaces in the process of name resolution firstthe most locally enclosing scope is searched for given name if not found therethe next outer scope is searchedand so on we will continue our examination of namespacesin section when discussing python' treatment of object-orientation we will see that each object has its own namespace to store its attributesand that classes each have namespace as well first-class objects in the terminology of programming languagesfirst-class objects are instances of type that can be assigned to an identifierpassed as parameteror returned by function all of the data types we introduced in section such as int and listare clearly first-class types in python in pythonfunctions and classes are also treated as first-class objects for examplewe could write the followingscream print screamhello assign name 'screamto the function denoted as 'printcall that function in this casewe have not created new functionwe have simply defined scream as an alias for the existing print function while there is little motivation for precisely this exampleit demonstrates the mechanism that is used by python to allow one function to be passed as parameter to another on page we noted that the built-in functionmaxaccepts an optional keyword parameter to specify non-default order when computing maximum for examplea caller can use the syntaxmax(abkey=abs)to determine which value has the larger absolute value within the body of that functionthe formal parameterkeyis an identifier that will be assigned to the actual parameterabs in terms of namespacesan assignment such as scream printintroduces the identifierscreaminto the current namespacewith its value being the object that represents the built-in functionprint the same mechanism is applied when userdefined function is declared for exampleour count function from section beings with the following syntaxdef count(datatarget)such declaration introduces the identifiercountinto the current namespacewith the value being function instance representing its implementation in similar fashionthe name of newly defined class is associated with representation of that class as its value (class definitions will be introduced in the next