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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_string(self):
 """ Get a string representation of this single base error. :returns: report :rtype: string """

    ostr = ''
    ostr += 'BaseError for ['+self._type+'] base: '+self.get_base()+"\n"
    if self._observable.get_error_probability() > 0:
      ostr += '  Homopolymer set:'+"\n"
      ostr += '    '+str(self.get_homopolymer())+"\n"
      ostr += '  Observable:'+"\n"
      ostr += '    type is: '+str(self.get_observable_type())+"\n"
      ostr += '    P(error): '+str(self._observable.get_error_probability())+"\n"
      ostr += '    Elength:  '+str(self._observable.get_attributable_length())+"\n"
    before = self._unobservable.get_before_type()
    after = self._unobservable.get_after_type()
    if before or after:
      ostr += '  Unobservable '
      if self._type == 'query': ostr += 'deletion:'+"\n"
      else: ostr += 'insertion:'+"\n"
      ostr += '    P(error): '+str(self._unobservable.get_error_probability())+"\n"
      ostr += '    Elength:  '+str(self._unobservable.get_attributable_length())+"\n"
      if before:
        ostr += '    before: '+"\n"
        ostr += '      P(error): '+str(self._unobservable.get_before_probability())+"\n"
        ostr += '      '+str(before)+"\n"
      if after:
        ostr += '    after:'+"\n"
        ostr += '      P(error): '+str(self._unobservable.get_after_probability())+"\n"
        ostr += '      '+str(after)+"\n"
    return ostr