Biological Virus simulation

import numpy
import random
import pylab

class SimpleVirus(object):

"""
    Representation of a simple virus (does not model drug effects/resistance).
    """
    def __init__(self, maxBirthProb, clearProb):
        """
        Initialize a SimpleVirus instance, saves all parameters as attributes
        of the instance.        
        maxBirthProb: Maximum reproduction probability (a float between 0-1)        
        clearProb: Maximum clearance probability (a float between 0-1).
        """
		self.maxBirthProb = maxBirthProb
		self.clearProb = clearProb

def getMaxBirthProb(self):
        """
        Returns the max birth probability.
        """
		return self.maxBirthProb
        # TODO

def getClearProb(self):
        """
        Returns the clear probability.
        """
		return self.clearProb
        # TODO

def doesClear(self):
        """ Stochastically determines whether this virus particle is cleared from the
        patient's body at a time step. 
        returns: True with probability self.getClearProb and otherwise returns
        False.
        """
		return self.clearProb > random.random()
        # TODO

def reproduce(self, popDensity):
        """
        Stochastically determines whether this virus particle reproduces at a
        time step. Called by the update() method in the Patient and
        TreatedPatient classes. The virus particle reproduces with probability
        self.maxBirthProb * (1 - popDensity).
        
        If this virus particle reproduces, then reproduce() creates and returns
        the instance of the offspring SimpleVirus (which has the same
        maxBirthProb and clearProb values as its parent).

popDensity: the population density (a float), defined as the current
        virus population divided by the maximum population.         
        
        returns: a new instance of the SimpleVirus class representing the
        offspring of this virus particle. The child should have the same
        maxBirthProb and clearProb values as this virus. Raises a
        NoChildException if this virus particle does not reproduce.               
        """
		repoProbability = self.maxBirthProb * (1 - popDensity)
		if(random.random() > repoProbability):
			raise NoChildException('In reproduce()')
			
		return SimpleVirus(self.maxBirthProb, self.clearProb)
        # TODO

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