[Tutor] Problem on select esecution of object in a class

[jarod_v6 at libero.it]

I have a class with many objects and I want to  select using opt parse some function
id = options.step
        ena = Rnaseq(options.configura, options.rst, options.outdir)
        now = datetime.datetime.now()
        ena.show()
        diz = {}
        for i,t in enumerate(ena.steps()):
            diz.setdefault(i,[]).append(t.__name__)
        
        for i in "ena."+"".join(diz[id])+"()":

            print i.command

 1 for i in "ena."+"".join(diz[id])+"()":
      2 
----> 3                 print i.command
      4 

AttributeError: 'str' object has no attribute 'command'


here you se what they ouptut
"ena."+"".join(diz[id])+"()"
Out[85]: 'ena.trimmomatic()

Definition: ena.trimmomatic(self)
Source:
        def trimmomatic(self):

                """
                Raw reads quality trimming and removing of Illumina adapters is performed using [Trimmomatic](http://www.usadellab.org/cms/index.php?page=trimmomatic).

                This step takes as input files:

                1. FASTQ files from the readset file if available
                
                """
                jobs = []
                for readset in self.readsets:
                        
                        trim_file_prefix = os.path.join(self.pt,"trim", readset.sample.name, readset.name + ".trim.")
                        trim_log = trim_file_prefix + "log"
                        trim_stats = trim_file_prefix + "stats.csv"
:

Any suggestion in how to choose the function to use?
M.