class RuboCop::Cop::Style::MethodName

have to be made for operator methods.
snake_case or camelCase, for their names. Some special arrangements
This cop makes sure that all methods use the configured style,

def message(style) 

def message(style)
  format('Use %s for method names.', style)
end

def on_def(node) 

def on_def(node)
  name, = *node
  check_name(node, name, node.loc.name)
end

def on_defs(node) 

def on_defs(node)
  _object, name, = *node
  check_name(node, name, node.loc.name)
end