def Identifiers(self, p):
     if len(p) == 0:
         return None
     if len(p) == 4:
         return Statement.IdentifierList(p[1], Expression.IdentifierExpression(p[2]), p[3])
     return Statement.IdentifierList(p[1], Expression.IdentifierExpression(p[2]))
 def FormalList(self, p):
     if len(p) == 0:
         return None
     if len(p) == 3:
         return Statement.IdentifierList(p[0], Expression.IdentifierExpression(p[1]), p[2])
     return Statement.IdentifierList(p[0], Expression.IdentifierExpression(p[1]))