class Prism::BeginNode

def ===(other)

comparing the value of locations. Locations are checked only for presence.
Implements case-equality for the node. This is effectively == but without 
def ===(other)
  other.is_a?(BeginNode) &&
    (begin_keyword_loc.nil? == other.begin_keyword_loc.nil?) &&
    (statements === other.statements) &&
    (rescue_clause === other.rescue_clause) &&
    (else_clause === other.else_clause) &&
    (ensure_clause === other.ensure_clause) &&
    (end_keyword_loc.nil? == other.end_keyword_loc.nil?)
end