venture of iit bombay vjti alumni nameerror raised when an identifier is not found in the local or global namespace unboundlocalerror raised when trying to access local variable in function or method but no value has been assigned to it environmenterror base class for all exceptions that occur outside the python environment ioerror raised when an inputoutput operation failssuch as the print statement or the open(function when trying to open file that does not exist ioerror