title: TypeError: unsupported operand type(s) for ** or pow(): 'function' and 'int'
body: <p>I don't know why i can x*<em>2 and y</em>*2
  please help i need this i dont get why im
  getting this error...
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  <pre><code>def regresion(lista,n):
  a=0
  b=0
  if isinstance(n,int):
      a =((x**2)(y**2)-n(promx)(promy)) / (((x**2)**2)-n(promx**2))
  
      b =(promy-(n)(promx**2))
  else:
      "n no es entero"
  return a,b
  
  def x(lista):
  a=[]
  c=0
  x=0
  if lista!=[]:
      for i in lista:
          c = i[0]
          a = a + [c]
      for i in a:
          x = x + i
  
      return x
  def y(lista):
  b=[]
  d=0
  y=0
  if lista!=[]:
      for i in lista:
              d = i[1]
              b = b + [d]
  
      for i in b:
              y = y + i
  
      return y
  def promx(lista):
  a=[]
  c=0
  x=0
  promx=0
  if lista!=[]:
      for i in lista:
          c = i[0]
          a = a + [c]
  
      for i in a:
          x = x + i
      promx= x / len(a)
  
      return promx
  def promy(lista):
  b=[]
  d=0
  y=0
  promy=0
  if lista!=[]:
      for i in lista:
              d = i[1]
              b = b + [d]
  
      for i in b:
              y = y + i
      promy= y / len(b)
  return promy
  </code></pre>