NewKeyword prepare the string to be used as a valid keyword if a invalid char is found then the returned keyword is marked as invalid and can't be used for processing.

Edge represent the connection between two nodes.

keyword is a shared identifier that can be used to identify node types, edge types and name properties All keywords should start with ":" to be considered valid.

Node represent the data stored in the graphdb.

Properties is a collection of keys and values (any valid Go type) that represent the data of a given node.