code: def fetch file_path, method_name, *required_params
        if self.index["#{file_path}"].nil? || self.index["#{file_path}"]["#{method_name}"].nil?
          return nil
        end
        λ_id = self.index["#{file_path}"]["#{method_name}"]['lambda_id']
        return self.cache[λ_id] ||= eval(File.read(".spectro/cache/#{λ_id}.rb"))
      end
docs: Fetches and returns the target lambda based on the
   given class, method name and required aprameters.
  
   @param [String] file_path relative path of the file that requests the lambda
   @param [Symbol] method_name the method name that would be implemented
   @param [<Symbol>] required_params parameters that would be required by the lambda
   @return [Proc] the labda that would be implemented