Python Identifiers

• The fundamental building blocks in a program known as identifier.
• These can be variables ,class ,object ,functions , lists , dictionaries etc.

There are certain rules defined for naming 

    1. An identifier is a long sequence of characters and numbers.

    2. No special character except _ (underscore)  can be used as an identifier.

    3. Identifier name can not same as keyword.

    4. using case is significant because python is case sensitive.

    5. First character of identifier can not be a digit.It must be start with character or _ (underscore).