def unIndentBlock(block):
            currentIndent = blockIndentation(block)

            if currentIndent.endswith('\t'):
                charsToRemove = 1
            elif withSpace:
                charsToRemove = 1 if currentIndent else 0
            else:
                if self.useTabs:
                    charsToRemove = min(spacesCount(currentIndent), self.width)
                else:  # spaces
                    if currentIndent.endswith(self.text()):  # remove indent level
                        charsToRemove = self.width
                    else:  # remove all spaces
                        charsToRemove = min(spacesCount(currentIndent), self.width)

            if charsToRemove:
                cursor = cursorAtSpaceEnd(block)
                cursor.setPosition(cursor.position() - charsToRemove, QTextCursor.KeepAnchor)
                cursor.removeSelectedText()
def test_lens_makers_formula():
    n1, n2 = symbols('n1, n2')
    m1 = Medium('m1', permittivity=e0, n=1)
    m2 = Medium('m2', permittivity=e0, n=1.33)
    assert lens_makers_formula(n1, n2, 10, -10) == 5*n2/(n1 - n2)
    assert ae(lens_makers_formula(m1, m2, 10, -10), -20.15, 2)
    assert ae(lens_makers_formula(1.33, 1, 10, -10),  15.15, 2)