Trains a Markov model from a collection of sequences. 

$USAGE$
<modelName> is the name of the Markov model. This name can be used by other commands to refer the trained Markov model.
<sequences> is the name of the sequences from which the model is trained in the storage.
<markovOrder> is optional and defines the memory length of the trained Markov model. The default value is 1.

Examples:
trainMarkovModel mm sequences
trainMarkovModel mm sequences 3