title: create a polynomial class, and when the class is called, it returns the polynomial equation in text form
body: <p>Firstly, add_term method, adds one term to a Polynomial. The method takes two inputs - the first is the coefficient value, and the second is the exponent value. <strong>str</strong> method should return a string that represents that polynomial,  The string returned by this method should use the ‘^’ character to indicate exponentiation. The following example shows a Polynomial with both a negative and positive exponent:</p>
  
  <p>Basic rules of polynomials should also apply, such as:
  - If the exponent is 0, then 'x' is not printed (i.e., 2 rather than 2x^0)
  - If the exponent is 1, then the exponent is not printed (i.e., 2x rather than 2x^1)
  - Only terms with non-zero coefficients should be displayed
  etc. </p>
  
  <p>I can't really grasp my head around the problem, really need somewhere to make a start with. Please Thank you </p>
  
  <pre><code>p1 = Polynomial()
  p1.add_term(123, 987654321)
  p1.add_term(-9, -987654321)
  print('p1 =', p1)
  #Output is Below
  123x^987654321 - 9x^-987654321
  #Another Example can be seen below
  
  p1 = Polynomial()
  p1.add_term(1, 3)
  p1.add_term(-4, 2)
  p1.add_term(-100, 25)
  p1.add_term(-66, 0) 
  print('p1 =', p1)
  #Output is below
  p1 = -100x^25 + x^3 - 4x^2 - 66 + 6x^-7
  </code></pre>
  
  <p>Expected result can be seen in the code</p>