def undef_cell(name)
      method_name = name.gsub('-', '_')
      
      klass = class << self; self; end
      klass.class_eval do
        remove_method(method_name)
      end
    end
def undef_cell(name)
      method_name = name.gsub('-', '_')
      
      klass = class << self; self; end
      klass.class_eval do
        remove_method(method_name)
      end
    end
Removes the definition for the given cell